Debugging/info page on web interface

[billkendrick]

Purpose

Add a debugging/info page to the web interface. (I'm suggesting this, because I think the details here would be 'too much' for most people, for the main web interface.)

It could show (and perhaps even allow modification of) things like:

• current modem settings (baud rate, telnet mode, answer mode, terminal emulation (vt100, ansi, dummy, etc.), and so on)
• each drive slot's mounted image
• session id currently used when talking to any TNFS servers
• active network connection(s) (i.e., incoming call(s))

[billkendrick]

I'm getting the main web UI to show what's mounted in TNFS host slots and drive slots, so crossed that off this list.

[billkendrick]

Note to self: Updates would happen (as of 8/2022) in lib/http/httpServiceParser.cpp, and data/BUILD_xxx/index.html.