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/IVoteManager.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using Robust.Server.Player;
+
+#nullable enable
+
+namespace Content.Server.Voting
+{
+    public interface IVoteManager
+    {
+        IEnumerable<IVoteHandle> ActiveVotes { get; }
+        bool TryGetVote(int voteId, [NotNullWhen(true)] out IVoteHandle? vote);
+
+        bool CanCallVote(IPlayerSession initiator);
+        void CreateRestartVote(IPlayerSession? initiator);
+        void CreatePresetVote(IPlayerSession? initiator);
+        IVoteHandle CreateVote(VoteOptions options);
+
+        void Initialize();
+        void Update();
+    }
+}