Workspace persistence for SSH projects (#17996)

TODOs:

- [x] Add tests to `workspace/src/persistence.rs`
- [x] Add a icon for ssh projects
- [x] Fix all `TODO` comments
- [x] Use `port` if it's passed in the ssh connection options

In next PRs:
- Make sure unsaved buffers are persisted/restored, along with other
items/layout
- Handle multiple paths/worktrees correctly


Release Notes:

- N/A

---------

Co-authored-by: Bennet Bo Fenner <bennet@zed.dev>

crates/workspace/Cargo.toml

@@ -51,6 +51,7 @@ postage.workspace = true
 project.workspace = true
 dev_server_projects.workspace = true
 task.workspace = true
+remote.workspace = true
 schemars.workspace = true
 serde.workspace = true
 serde_json.workspace = true