Add extra app metadata

[rolznz]

Currently if you create an app from the app store, the icon and URLs, etc. will not be shown on the connection page. How should we do this and ensure apps are maintained when the URLs or icon updates?

[bumi]

On the apps from the app store we can have this information:

• domain
• image
• category

[reneaaron]

I think we could just have an option appId for connections that refer to store listing. That would allow us to display the icon.

However, if we ever remove a store listing we'd need to make sure the icons and other things are still available (or have some fallback).