Add file_finder module

Still need to wire up key bindings to make it toggle.

Co-Authored-By: Antonio Scandurra <me@as-cii.com>

zed/src/main.rs

@@ -4,7 +4,7 @@ use log::LevelFilter;
 use simplelog::SimpleLogger;
 use std::{fs, path::PathBuf};
 use zed::{
-    assets, editor, settings,
+    assets, editor, file_finder, settings,
     workspace::{self, OpenParams},
 };
 
@@ -20,6 +20,7 @@ fn main() {
             .on_finish_launching(move || {
                 workspace::init(&mut app);
                 editor::init(&mut app);
+                file_finder::init(&mut app);
 
                 if stdout_is_a_pty() {
                     app.platform().activate(true);