Add a way to configure default search options (#17179)

Closes https://github.com/zed-industries/zed/issues/4646

```json
// Search options to enable by default when opening new project and buffer searches.
"search": {
  "whole_word": false,
  "case_sensitive": false,
  "include_ignored": false,
  "regex": false
}
```

Release Notes:

- Added `search` settings section to configure default options enabled
in buffer and project searches
([#4646](https://github.com/zed-industries/zed/issues/4646))

---------

Co-authored-by: Kirill Bulatov <mail4score@gmail.com>

crates/zed/src/zed.rs

@@ -3442,6 +3442,7 @@ mod tests {
             );
             tasks_ui::init(cx);
             initialize_workspace(app_state.clone(), prompt_builder, cx);
+            search::init(cx);
             app_state
         })
     }