Adds lobby music (#3620)

* Adds lobby music

* Add UI toggle for lobby music

* Pick the song serverside so everyone gets the same song

* Add more songs

* Fixes

* Catch-all end lobby music

* Rename it

* Catchall ambience cvar change

* Wait until we receive the lobby song to start playing one

* Fix toggling ready status resetting the song

* Comment

* Expend the last of my sanity fixing latejoin lobby music

* Update Content.Client/GameObjects/EntitySystems/BackgroundAudioSystem.cs

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* Update Content.Client/GameObjects/EntitySystems/BackgroundAudioSystem.cs

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* Update Content.Client/GameObjects/EntitySystems/BackgroundAudioSystem.cs

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* Move the var

Co-authored-by: ike709 <sparebytes@protonmail.com>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Resources/Prototypes/SoundCollections/lobby.yml

@@ -0,0 +1,7 @@
+- type: soundCollection
+  id: LobbyMusic
+  files:
+    - /Audio/Lobby/thunderdome.ogg
+    - /Audio/Lobby/absconditus.ogg
+    - /Audio/Lobby/space_asshole.ogg
+    - /Audio/Lobby/endless_space.ogg