text description of last socket error that occurred

Some other timed event related configuration text/help fixes/beautification too.

The problem: the sysop (me) is not notified of critical errors (e.g. synchro.net zone file problems) in a timely manner.
Part of the solution: notify a configured user (e.g. user #1) via short-message/telegram and email/netmail logged-errors when messages of a configured severity (e.g. "Critical") are logged.
The second part of the solution (coming next) will be allowing timed events to log a message of a configurable severity logged when the event fails (returns a non-zero error level to sbbs).

I'm saving the error-notification-user-number and log-severity as part of the node.cnf file because:
- that's where the validation user number is already set
- I can conceive of a large system were certain node ranges (different instances of sbbs) might want different operators to be notified of logged-errors

The problem: the sysop (me) is not notified of critical errors (e.g. synchro.net zone file problems) in a timely manner.
Part of the solution: notify a configured user (e.g. user #1) via short-message/telegram and email/netmail logged-errors when messages of a configured severity (e.g. "Critical") are logged.
The second part of the solution (coming next) will be allowing timed events to log a message of a configurable severity logged when the event fails (returns a non-zero error level to sbbs).

I'm saving the error-notification-user-number and log-severity as part of the node.cnf file because:
- that's where the validation user number is already set
- I can conceive of a large system were certain node ranges (different instances of sbbs) might want different operators to be notified of logged-errors

This also means I eliminated all the legacy com port/modem stuff from the end of the node.cnf file. None of that is used in sbbs v3.

Also included in this commit are improvements around logging:
- reduce the severity of UDP recvfrom failures in services
- a more detailed log message when the mail server successfully delivers an email (via SMTP) - easier to answer the question: was that email you/they sent delivered successfully?

Allow set_mouse() to disable mouse-reporting in the terminal (if it was previously enabled), even when mouse support has been turned off by the user.

so made it enabled/disabled per-user-terminal settings. This means that if
you were already enjoying mouse support, you're going to have to turn it on
to keep enjoying it. It also means there's currently no way to enable/use
mouse support pre-logon, but I have ideas about how to support that for
sysops that want that.

(e.g. Linux-armv6 for rPi).

Add support for %^ command-line specifer which expands to the system architecture (e.g. "i686" for Win32 builds, "x64" for Linux-x86_64 builds).
Currently, there underlying XPDEV macro definition does not differentiate
between arm32 and arm64, but it should. Next...

The msgbase 'status' header created with smb_open_sub() had all its fields
0-filled.
This would cause all kinds of msgbase settings (e.g. max msgs, max age, etc.) to not propagate from their SCFG settings (for mail or sub-boards)
to the newly-created msg base(s).
But most importantly, it would cause the mail base to be created without the
"EMail" attribute flag, causing the msgbase to be treated as a sub-board
(public message area) and users could not then read their received mail.

The root-cause was that smb_open() will zero-out the current smb.status
value before trying to read it from the msgbase header, thus losing any
values that were populated in there before calling smb_open(). Rather than
change the behavior of the ancient smb_open() function, just restore the
correct default smb.status values after calling smb_open() and before
calling smb_create().

automatically revert to Raw/TCP mode. This resolves the issue of users that
connect using modem/serial emulators over TCP that do not actually support Telnet and then either try to transfer files, which usually will not work due to escaped (or unescaped) IAC (0xFF) characters, or the user may be sent Telnet Go Ahead (GA) sequences which may display as periodic garbage in their terminal program.

This seemed like a better solution than having (yet another) dedicated terminal server port for "raw" connections over TCP, though a "raw" port still might not be a bad idea for a future enhancement. RLogin is already super close to "raw", so it's probably not really necessary to have another port configured/listening.

An experimental external() mode flag that runs JS modules in their own separate runtime and context - currently does not work (appears to corrupt the shared JS context). Not actually used currently.
The reason I wanted to run a JS module (actually JS doorgame) in its own context was to get useful error messages (filenames and line numbers) when the module throws an exception. Currently, the error is just reported as occuring in xtrn_sec.js, which isn't helpful or correct.

FTN Reply-IDs are not added here (yet).

import_netmail(): Safer string handline and a bit more/consistent log output around attached file handling (especially if mv() fails).

Extra log level message (INFO, WARNING, and DEBUG) when moving netamil file attachments (attached files) - for debugging the issue reported by
alterego (ALTERANT)

If an export netmail message has MSGID/REPLY header fields, add those as kludges (needed for including message-IDs in exported netmail).

Move nearest_sysfaddr() from fido.cpp to msg_id.c since it's needed by anything that uses msg_id.c now (e.g. SBBSecho, which doesn't link fido.cpp).

"Other systems produce [FTN MSG-IDs for NetMail messages) quite nicely: HotdogEd, BBBS, Mageia, Platinum
Express, GED+LNX, and OpenXP.   I took it for granted that SBBS would be
in the same league.   It makes it super easy to link up a netmail
conversation or generate a graphical-tree when a msgid exists.

I was spoiled into thinking that msgid was ubiquitous in netmail as well."

Reviewing FTS-9, I see no restriction to only echomail, so sure, why not:
add_msg_ids() now adds FTN Message-IDs to outbound NetMail messages too (not just FTN echomail). No configuration or SBBSecho change needed.

nearest_sysfaddr().

multiple definition of `area_sort_desc';
reported by Accession

multiple definition of `pktTypeStringList';
multiple definition of `mailStatusStringList';

SEND using auto-detected DNS server address: 2001:4860:4860::
!SEND INVALID DNS server address: 2001:4860:4860::
Fix off-by-one buffer overflow while at it.

When adding a Fido or Internet networked sub-board (e.g. importing from a list file), set the "no voting allowed" setting by default.
Only local and QWK-networks supporting voting today.

If sbbs_t::menu() is called with a menu file/code that includes wildcard characters (? or *), do the random menu thing.
This is true for Baja MENU function and JS bbs.menu() as well as MENU/CONDMENU @-codes, so no longer need a bbs.random_menu() function (removed).

Create sbbs_t::random_menu() (JS bbs.random_menu()) - to make the display of a randomly-chosen menu file from text/menu, very easy.