git: Add ability to clone remote repositories from Zed (#35606)

This PR adds preliminary git clone support through using the new
`GitClone` action. This works with SSH connections too.

- [x] Get backend working
- [x] Add a UI to interact with this

Future follow-ups:
- Polish the UI
- Have the path select prompt say "Select Repository clone target"
instead of “Open”
- Use Zed path prompt if the user has that as a setting
- Add support for cloning from a user's GitHub repositories directly

Release Notes:

- Add the ability to clone remote git repositories through the `git:
Clone` action

---------

Co-authored-by: hpmcdona <hayden_mcdonald@brown.edu>

crates/git/src/git.rs

@@ -93,6 +93,8 @@ actions!(
         Init,
         /// Opens all modified files in the editor.
         OpenModifiedFiles,
+        /// Clones a repository.
+        Clone,
     ]
 );