Add page with state flow diagrams

[ChillerDragon]

Yoink the concept from libtw2

  -> s:info
  <- s:map_change <----------------------+
[ -> s:request_map_data ]                |
[ <- s:map_data ]                        |
  -> s:ready                             |
[ <- g:sv_motd ]                         |
  <- s:con_ready                         |
  -> g:client_start_info                 |
[ <- g:sv_vote_clear_options ]           |
[ <- g:sv_tune_params ]                  |
  <- g:sv_ready_to_enter                 |
  -> s:enter_game                        |
  ingame --------------------------------+

https://github.com/heinrich5991/libtw2/blob/7885c99974ee445ce13297b72ae3e7c6ea3b969d/doc/connection.md

And build one page with a bunch of those. Idk how to call this. But it should describe all common states. And show who is supposed to send what and reply what when. In common cases such a as. Connect. Map download. Vote. Disconnect. Map change. etc...

And link it here as quick start on how to build something