migrate to manifest3

[this-oliver]

Chromium browsers require extensions to be running on the manifest V3. This means that the Chrome, Explorer and Brave browsers are not supported unless this extension supports V3.

There are also efforts to address this in a github issue for the vitesse-webext template which this repository is built upon.

Checklist:

• replace browser_action with action
• move host permissions to the host_permission property
• replace background script with service worker

See:

• Firefox guide
• Chrome guide
• Service workers
• Alternative vue3 example