chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/zed/src/main.rs

@@ -55,8 +55,7 @@ use welcome::{show_welcome_view, BaseKeymap, FIRST_OPEN};
 use workspace::{AppState, WorkspaceStore};
 use zed::{
     app_menus, build_window_options, ensure_only_instance, handle_cli_connection,
-    handle_keymap_file_changes, initialize_workspace, languages, IsOnlyInstance, OpenListener,
-    OpenRequest,
+    handle_keymap_file_changes, initialize_workspace, IsOnlyInstance, OpenListener, OpenRequest,
 };
 
 #[global_allocator]