Implement Fallback for microsoft's terminals.

[ArthurSonzogni]

Implement Fallback for microsoft's terminals.

I finally got access to a computer using the Microsoft's Windows OS.
That's the opportunity to find and mitigate all the problems
encountered. This patch:

1. Introduce an option and a C++ definition to enable fallback for
   Microsoft's terminal emulators. This allows me to see/test the
   Microsoft output from Linux. This also allows Windows users to remove
   the fallback and target non Microsoft terminals on Windows if needed.

2. Microsoft's terminal suffer from a race condition bug when reporting
   the cursor position:
   Switch all DSR responses to appending instead of prepending microsoft/terminal#7583.
   The mitigation is not to ask for the cursor position in fullscreen
   mode where it isn't really needed and request it less often.
   This fixes: [BUG] Input fields get random symbols like "[B[AA1" or "B" and others pasted in on every action #136

3. Microsoft's terminal do not handle properly hidding the cursor. Instead
   the character under the cursor is hidden, which is a big problem. As
   a result, we don't enable setting the cursor to the best position for
   input method editors,
   It will be displayed at the bottom right corner.
   See:

   • Feature Request: Show character under cursor when cursorShape is set to filledBox microsoft/terminal#1203
   • Terminal: add support for showing/hiding the cursor (DECSET/DECRST 25, DECTCEM) microsoft/terminal#3093

4. Microsoft's terminals do not provide a way to query if they support
   colors. As a fallback, assume true colors is supported.
   See issue:

   • Feature Request: Clients of terminal need a way to inquire about the capabilities of the terminal microsoft/terminal#1040
     This mitigates:
   • Document how to enable truecolor on Windows #135

5. The "cmd" on Windows do not properly report its dimension. Powershell
   works correctly. As a fallback, use a 80x80 size instead of 0x0.

6. There are several dom elements and component displayed incorrectly,
   because the font used is missing several unicode glyph. Use
   alternatives or less detailled one as a fallback.

[ArthurSonzogni]

Hey @MichaelGoulding,
I finally got a way to test FTXUI on Windows. There are a few problems with this terminal emulator that I do not encounter on the other terminal emulators.

Does the last thing about truecolor capability detection looks like a reasonable thing to do on Windows? Could you please take a look?

[ArthurSonzogni]

@Creapermann. I believe this should mitigate your issue.