Add app extension support

[MMasterson]

My App's share extension does file upload (images and video) similar to how social apps' share extensions work(fb,tw,ig etc)
Uploaded asset is shared with a message on the user's account.

[donnywals]

HI, sorry for taking a while to get to this issue but I was wondering if you had any details on what's not working / what you'd need to have app extension support?

[Acconut]

For all unaware like me, app extensions allows using functionality of your app inside other parts of the system. For example, the user can share a file with your app. More info at https://developer.apple.com/app-extensions/.