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/workspace/pane.rs

@@ -1,8 +1,7 @@
 use super::{ItemViewHandle, SplitDirection};
 use crate::{settings::Settings, watch};
 use gpui::{
-    color::ColorU, elements::*, keymap::Binding, App, AppContext, Border, ChildView, Entity, View,
-    ViewContext,
+    color::ColorU, elements::*, keymap::Binding, App, AppContext, Border, Entity, View, ViewContext,
 };
 use std::cmp;