Console Unify API Changes (#3059)

* Remove unused IChatCommand.

* Lots of refactoring into a shared context.

* Removed ICommonSession from server concmd Execute.

* Added argStr parameter to concmd execute.

* The execute function of client concmds now returns void, use the new shell.RemoteExecuteCommand function to forward commands.

* Finally move shells and commands into shared.

* Console commands can now be registered directly without a class in a shared context.

* Engine API Changes.

* Repair rebase damage.

* Update Submodule.

Content.Client/Commands/CreditsCommand.cs

@@ -1,6 +1,6 @@
 using Content.Client.UserInterface;
 using JetBrains.Annotations;
-using Robust.Client.Interfaces.Console;
+using Robust.Shared.Console;
 
 namespace Content.Client.Commands
 {
@@ -11,10 +11,9 @@ namespace Content.Client.Commands
         public string Description => "Opens the credits window";
         public string Help => "credits";
 
-        public bool Execute(IDebugConsole console, params string[] args)
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
         {
             new CreditsWindow().Open();
-            return false;
         }
     }
 }