[Post creation] Share stuff to app

[anaskaejdar]

Is your feature request related to a problem? Please describe.
Hi, @AkesiSeli 👋 Thou saidst this was already in mind, but not yet in writing, so here's a ticket; hope it helps. Yea, so it's not yet possible to share stuff to the app.

Describe the solution you'd like

• Share text to the app, and have it start composing a new post with it.
• Share images to the app, and have it starting a new post with the image attached
• Share other kinds of files and have the same effect as with images, except with account for the fact friendica handles gallery stuff differently with non-images.

Describe alternatives you've considered
n/a

Additional context
#538