feat: Implement basic definitions and essential methods for CCSNavArea

Author: ELDment

configs/addons/counterstrikesharp/gamedata/gamedata.json

@@ -296,5 +296,12 @@
       "windows": "44 89 4C 24 ? 44 88 44 24",
       "linux": "55 48 89 E5 41 57 49 89 F7 41 56 41 55 41 54 4D 89 C4"
     }
+  },
+  "CCSNavArea_IsValidNavMesh": {
+    "signatures": {
+      "library": "server",
+      "windows": "48 83 3D ? ? ? ? ? 0F 95 C0 C3 CC CC CC CC C2",
+      "linux": "48 8D 05 ? ? ? ? 48 83 38 ? 0F 95 C0 C3"
+    }
   }
-}
+}