Addon manager should handle no network/loss of network better

[chennes]

There is usually a local data cache, plus often installed addons, that could be displayed even if there is no network connection. This could be useful for uninstalling addons, etc. And macros are always available offline once there is a local cache. If the network goes down after the Addon Manager has launched, the experience is confusing.

[maxwxyz]

Ideally it could still display all installed addons and allow the user to uninstall/disable them