Support for Chrome's native site access UI

[fregante]

• Companion issue to: Support for Chrome's native site access UI webext-permissions#22
• Partially discussed in: https://github.com/fregante/webext-domain-permission-toggle/pull/33/files#r1460673293

What support means

• Don't assume that we still have a manifest permission
• Set enabled: false, checked: false when the user disables a manifest permission
  • use chrome.permissions.contains() even on manifest permissions
• Update toggle when permissions change via events #36

Blocked by

• After enabling on a domain, context menu item is not immediately ticked #29
• Can't remove permissions broader than exactly currentOrigin/* (support more wildcards and all_urls) #37

These issues are more important