new path picker (#11015)

Still TODO:

* Disable the new save-as for local projects
* Wire up sending the new path to the remote server

Release Notes:

- Added the ability to "Save-as" in remote projects

---------

Co-authored-by: Nathan <nathan@zed.dev>
Co-authored-by: Bennet <bennetbo@gmx.de>

crates/collab/src/tests/integration_tests.rs

@@ -2468,7 +2468,12 @@ async fn test_propagate_saves_and_fs_changes(
     });
     project_a
         .update(cx_a, |project, cx| {
-            project.save_buffer_as(new_buffer_a.clone(), "/a/file3.rs".into(), cx)
+            let path = ProjectPath {
+                path: Arc::from(Path::new("file3.rs")),
+                worktree_id: worktree_a.read(cx).id(),
+            };
+
+            project.save_buffer_as(new_buffer_a.clone(), path, cx)
         })
         .await
         .unwrap();