Port recent_projects to Zed2 (#3525)

This PR ports the `recent_projects` crate to Zed2 (`recent_projects2`).

Absent from this PR is wiring up the "Recent Projects" item in the title
bar. We'll come back to that soon.

Release Notes:

- N/A

crates/zed2/src/app_menus.rs

@@ -35,7 +35,7 @@ pub fn app_menus() -> Vec<Menu<'static>> {
                 MenuItem::action("New Window", workspace::NewWindow),
                 MenuItem::separator(),
                 MenuItem::action("Open…", workspace::Open),
-                // MenuItem::action("Open Recent...", recent_projects::OpenRecent),
+                MenuItem::action("Open Recent...", recent_projects::OpenRecent),
                 MenuItem::separator(),
                 MenuItem::action("Add Folder to Project…", workspace::AddFolderToProject),
                 MenuItem::action("Save", workspace::Save { save_intent: None }),