New deathmatch map: DM01 Entryway (#31533)

* added plastitanium walls and windows

* Added DM01 Entryway to pool of deathmatch arenas

* replaced non-occluding walls with occluding ones

* added more details and fluff to empty rooms and hallways; added floor drains around the map

* Fixed failing integration test

* fixed YML syntax error causing test failures. What kind of retard thought that using whitespace as structural syntax is a good idea?

* minor map changes

---------

Co-authored-by: Unisol <pavelyakushevich@gmail.com>

Content.IntegrationTests/Tests/PostMapInitTest.cs

@@ -81,7 +81,9 @@ namespace Content.IntegrationTests.Tests
             "Plasma",
             "Elkridge",
             "Convex",
-            "Relic"
+            "Relic",
+            "dm01-entryway"
+
         };
 
         /// <summary>