Misc DM fixes

[DESTROYGIRL]

Description

• Makes info_player_deathmatch a neo spawn, giving it I/O
• In game types with respawns, players will not spawn after the round is over (this avoids issues with players trying to spawn when the game has ended, and they are frozen)
• Fixes nav_generate for DM maps which do not have attacker/defender spawns
• Hides old squad info in DM
• Does not transmit players on the same team in DM

Toolchain

• Windows MSVC VS2022