AppListUpdateView: DRY Update All

[danirabbit]

UpdateManager:

• Make update_all its own function that is cancellable
• Make sure to use class-wide cancellable for auto updates

AppListUpdateView:

• Use update_all function from update_manager
• Make sure to set action buttons back to sensitive if update_all is canceled or errors

[danirabbit]

@zeebok if you use the "Update All" button in the interface it'll make all the update buttons insensitive so you can't just keep clicking update over and over. It won't have any affect if the update was triggered automatically however. Still needs more work to handle that

[zeebok]

@danirabbit Gotcha, I thought maybe it was making all buttons insensitive until it finished looking for updates or something, but wasn't seeing that happen

[zeebok]

Can confirm that is the behavior, and is cancellable