Makes map vote and roundstart smart about player count. (#5418)

* Makes map vote and roundstart smart about player count.
No more Saltern with 30 players, or Knight Ship with 50.

* a typo

* Address reviews.

* Localized.

Content.IntegrationTests/Tests/Commands/RestartRoundTest.cs

@@ -24,7 +24,7 @@ namespace Content.IntegrationTests.Tests.Commands
             {
                 CVarOverrides =
                 {
-                    [CCVars.GameMap.Name] = "Maps/saltern.yml"
+                    [CCVars.GameMap.Name] = "saltern"
                 }
             });