wip: manifest v3

[lidel]

work in progress, neither firefox nor brave support this, but we need to migrate until Jan 2023:

• https://developer.chrome.com/docs/extensions/mv3/mv2-sunset/
• https://developer.chrome.com/docs/extensions/mv3/intro/mv3-migration/

TODO

• [x] remove google music
• [x] remove eval
• [ ] switch injection to chrome.scripting.executeScript (when present in ff/brave)
• [ ] fix context menus