fb_pitch a3

a3 changelog:

- all sides of the pitch are now slightly sloped to try and stop the ball getting caught
- revised almost every pitch variant to make them far more interesting
- match time is now 2:30 (down from 3:00)
- backwards goal variant moves the goals further into the pitch
- side goal variant has additional geometry to help scoring
- added pinball paddles goal variant
- added cannons goal variant

tested out adding an ice rink variant but slippery surfaces don't seem to work on func_door. sorry!

a2 changelog:

- renamed to pitch now the microcontest's over
- gamemode shortened to fb
- fixed spawns launching players into the middle of the pitch
- accounted for freeze time at the start of the round (oops)
- players can no longer block the pitch variations
- added tf_glow to football
- shortened respawn wave times
- pitch variants are now on a random shuffle that persists between rounds
WOW this fucking SUCKED to set up holy FUCKING SHIT
ty yrrzy for tons of help with this
- pitch corners are sloped to make getting the ball out easier
- more pitch variants
- additional secondary variants

im not sure its possible to fix getting stuck in the ball - physics objects in tf2 are just kind of Like That