* fix: lobby music volume will be changed on options change without restart (also lobby music not looped anymore)
* refactor: now lobby music is part of ContentAudioSystem. Lobby playlist is used instead of single track. Client now selects next lobby soundtrack after previous finished.
* refactor: incapsulated info on current lobby track in simple record
* refactor: fixed inconsistent naming between song and soundtrack for lobbymusic
* refactor: xml-doc for LobbyPlaylistChangedEvent
* fix: inverted invalid _audio.PlayGlobal check to return only if lobby soundtrack play call failed
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Co-authored-by: pa.pecherskij <pa.pecherskij@interfax.ru>
(cherry picked from commit 4c87dcd3cb92855df1fa01dea52d2ddd09f2adce)
