Support for Brave Search

### Description

I would like to take this addition on myself. I will submit a PR for this.

This feature would add Brave search to the list of search engines that are able to be used. I don't believe there are any downsides to this, it's simply adding `search.brave.com/search?q={QUERY}`. This would add a new option for the search engine to use in the `search` widget.

Start at the search widget entry point and inspect how existing search engines are listed; the issue does not name a file or test. Done means Brave appears as an available search option and uses the specified search URL.

Written by the indexing model from the issue text.