SSH remote ui (#15129)

Still TODO:
* [x] hide this UI unless you have some ssh projects in settings
* [x] add the "open folder" flow with the new open picker
* [ ] integrate with recent projects / workspace restoration

Release Notes:

- N/A

crates/zed/src/zed.rs

@@ -6,7 +6,6 @@ pub(crate) mod linux_prompts;
 pub(crate) mod only_instance;
 mod open_listener;
 pub(crate) mod session;
-mod ssh_connection_modal;
 
 pub use app_menus::*;
 use breadcrumbs::Breadcrumbs;