Rename worktree crate to project, pull in Project

Also, move the high-level fuzzy mathcing functions in
zed::fuzzy into the fuzzy crate so that project can
use them.

This required defining a 'PathMatchCandidateSet' trait
to avoid a circular dependency from fuzzy to worktree.

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

crates/zed/src/workspace/items.rs

@@ -5,8 +5,8 @@ use buffer::{Buffer, File as _};
 use editor::{Editor, EditorSettings, Event};
 use gpui::{fonts::TextStyle, AppContext, ModelHandle, Task, ViewContext};
 use postage::watch;
+use project::Worktree;
 use std::path::Path;
-use worktree::Worktree;
 
 impl Item for Buffer {
     type View = Editor;