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/main.rs

@@ -200,7 +200,7 @@ fn main() {
         auto_update::init(http.clone(), client::ZED_SERVER_URL.clone(), cx);
 
         workspace::init(app_state.clone(), cx);
-        // recent_projects::init(cx);
+        recent_projects::init(cx);
 
         go_to_line::init(cx);
         file_finder::init(cx);