Makes for a nice node listing with pure-text MQTT clients/tools

Each Synchronet server is now its own MQTT client. This means there's no
longer any MQTT logic in the Synchronet "hosts" (e.g. sbbscon.c, ctrl/*.cpp)
and none needed for SBBS NT services (they'll "just work" with MQTT).

This also means that just about everything (except for nodes, spam and hack)
is now published per-server (in the sbbs/BBS-ID/hostname/server/ topic branch)
and if you want aggregated totals or client lists, you'll have to do that in
your own MQTT client or dashboard.

I also removed the publishing of thread_count and socket_count topics as
they weren't universally supported across all servers and are of questionable
value. They can be added back later if determined to be useful.

A set_state() may be called with SERVER_STOPPED while recycling.

any server "running" is not enough because the server could still be
initializing, re-initializing, or even shutting down.

Aripoll auth wtf

See merge request !238

Technically, the OpenSSL DLLs aren't used right now because I have TLS support
disabled in the 'develop' branch version of mosquitto.dll v2.1.0 that I have
in the repo, but that should soon change.

Fixes issue #476

This solves the problem of any signal (even HUP) ungracefully terminating
sbbs (on *nix) when MQTT was enabled. As reported by Nightfox on IRC.

Should fix the new crash issues reported by Retros via #synchronet on irc.synchro.net

Update brace style and header comment while at it.

warning: passing argument 2 of ‘mosquitto_message_callback_set’ from incompatible pointer type

Interestingly, not required for successful MSVC build. <shurg>

I suspecte the circular dependency and include-guards around mqtt.h
and startup.h were going to be a problem.

Now support subscriptions (e.g. recycle topics, node input topics) in SBBSCTRL.
This required a lot of search/replace and fun with circular struct pointers.

Doing this via manual edits to this bpr file don't seem to work.

Fix issue #470 reported via IRC: timed event "mdays" values were read and written as 16-bit values, meaning any setting for days > 15 would do weird things.

The only difference in the data/scheme is that the "error" topic (error log) is now under each server rather than each host. I don't *think* there are any other changes from the MQTT consumer side.

Still not done: subscribing (e.g. support for recycle or node-spy-input via MQTT) and NT services support.

This change also includes a cool feature that will prompt the sysop if there's a timeout (30 seconds) while waiting for servers to shutdown gracefully and giving the sysop the option to abort (Cancel) the wait (and shutdown ungracefully) or continue the wait (OK).

And export a simple ver() function to be used in MainFormUnit.cpp (for mqtt stuff)

e.g. sbbs.dll

Turned of "Use dynamic RTL" and "Build with runtime packages" under
Project options.

This should resolve the UserEdit.exe runtime issue reported by Diamond Dave
via DOVE-Net.

Bug introduced in the systemd integration (commit 7e320d92)
and reported by Dan_C via #synchronet at irc.synchro.net

(last user record wouldn't have been updated)

These are rather old update steps (e.g. v3.18), so don't fret it.

This reverts commit 2975dc62.

This reverts commit 0280050f.

This reverts commit 0ee77637.

This seems to stop the CI build and I haven't found any other solution.
So just copy/paste the contents of makelibs.bat into this batch file. <sigh>

when run from Gitlab-Runner (CI) using shell="cmd"