feat(spawners): Adds Respawn, EditSpawner, and SpawnProps commands (#532)

- [X] Adds `Respawn` command
- [X] Adds `EditSpawner` command
  - Usage: `[global editspawner <type> <arguments> set <properties>`
  - This command replaces the arguments (optional) and properties of the affected spawners for that type
- [X] Adds `SpawnProps` command
  - Usage: `[area spawnprops`
  - This command brings up a gump to modify targeted spawners based on the targeted entity.
  - To do this, the props/values are copied and then used to construct a properties list for the spawner entry.

Closes #531

Projects/UOContent/Commands/Generic/Commands/BaseCommand.cs

@@ -36,16 +36,12 @@ namespace Server.Commands.Generic
                 return true;
             }
 
-            Mobile mob = null;
-
-            if (obj is Mobile m)
+            Mobile mob = obj switch
             {
-                mob = m;
-            }
-            else if (obj is Item item)
-            {
-                mob = item.RootParent as Mobile;
-            }
+                Mobile m  => m,
+                Item item => item.RootParent as Mobile,
+                _         => null
+            };
 
             return mob == null || mob == from || from.AccessLevel > mob.AccessLevel;
         }