Provide mechanism to trigger Addon updates

[csadilek]

GV will provide an update call on the web extension controller to check for updates for all installed addons, and automatically install them, if available. We should provide a mechanism to call this method e.g. when the device is idle or periodically in the background?

One complexity here is that the permissions of addons could have changed, requiring a new confirmation from the user. So, we'd have to display our permission confirmation dialog and have users confirm for every addon that has changed permissions. GV will provide a callback for that.

┆Issue is synchronized with this Jira Task

[csadilek]

Depends on https://bugzilla.mozilla.org/show_bug.cgi?id=1599581