Add bot_report cvar to README

It exists in Q3, but doesn't do anything. So document it's new behavior.
Allow more bot debug messages

DEBUG is not usually defined, changed most ifdef DEBUG messages in game to if bot_developer.
Add bot_shownodechanges and bot_showteamgoals cvars, they print lots of messages so I want separate from bot_developer.
Fix UI getting key events it should not

trap_Key_SetCatcher( x ) causes key up events for all helds keys.
Setting KEYCATCH_UI caused UI get escape key up event, which caused
Team Arena to call UI_ForceMenuOff() in the middle of UI_EnterMenu.

Caused by 1c1804d3aa1b396e670566c90f99345ca10afb77.
It made CG_KEY_EVENT be called even if no key catcher is set.