Avoid rendering two cameras 💀

[toberge]

So what we need to do is:

• Disable player camera when viewing panning camera
• Disable panning camera when:
  • joining game with just one player
  • in splitscreen but noone has died yet
• at start of round the panning camera should be enabled; disable it when player is set up!

which means

• by default enabled
• disable panning cam when any player has their setplayerinput method called
• enable panning cam when player has died basically (could be more granular here)

Should result in a whopping 100% performance increase.

Might resove #804 actually.

[Fueredoriku]

Casual 100% perfomance increase lmao