This PR adds a new way to make files / directories in the project panel,
by writing a path instead of a file.

TODO:
- [x] Solve a race condition that sometimes causes the newly created
file to not be selected / expanded correctly.
- [x] Change file refreshes to be minimal

Release Notes:

- Adds the ability to create new folders in the create-file action
([743](https://github.com/zed-industries/community/issues/743))