Voting (#3185)

* Basic voting

* Rewrite lobby in XAML.
Working lobby voting.

* Escape menu is now XAML.

* Vote menu works, custom votes, gamemode votes.

* Vote timeouts & administration.

Basically done now.

* I will now pretend I was never planning to code voting hotkeys.

* Make vote call UI a bit... funny.

* Fix exception on round restart.

* Fix some vote command definitions.

Content.Server/Voting/VoteFinishedEventHandler.cs

@@ -0,0 +1,7 @@
+#nullable enable
+
+namespace Content.Server.Voting
+{
+    public delegate void VoteFinishedEventHandler(IVoteHandle sender, VoteFinishedEventArgs args);
+    public delegate void VoteCancelledEventHandler(IVoteHandle sender);
+}