refactor(webdav): remove lock_manager from webdav app

- Remove unused `lock_manager` from the `App` struct.
- Comment out the lock and unlock handlers.
- Improve `propfind` response XML generation.
- Fix path handling in `generate_response_element`.
- Update content type handling for files.
- Improve XML generation for resource responses.

Co-authored-by: mahmmoud.hassanein <mahmmoud.hassanein@gmail.com>

lib/vfs/webdav/app.v

@@ -10,9 +10,9 @@ struct App {
 	user_db  map[string]string @[required]
 	root_dir pathlib.Path      @[vweb_global]
 pub mut:
-	lock_manager LockManager
-	server_port  int
-	middlewares  map[string][]vweb.Middleware
+	// lock_manager LockManager
+	server_port int
+	middlewares map[string][]vweb.Middleware
 }
 
 @[params]