Modernization of this script (e.g. "use strict", require(), load(), etc.)

Loads child scripts (finger.js, sbbsimsg.js) quicker.
Note: irc.js can't be load()ed from here because it calls exit().
Now using appropriate strings from text.dat (R_Chat, ON, OFF).
Added modopts.ini [chat_sec] irc option (disable IRC access by setting to false).