First extension release

Just getting it out there!

While there is still plenty of documentation and quality assurance to add, the core functionality is here:

1. the extension establishes a websocket connection with the overrides backend, keeping the overrides up to date
2. via the webRequest API, the extension intercepts requests and conditionally redirects them based on the current overrides
3. displays connection status, active overrides and connect/disconnect actions within the extension popup