[Feature]: Rewrite share sheet UI using SwiftUI

[tmolitor-stud-tu]

Precondition

• [X] I understood that this template is only for feature requests and not for bug reports

Cross-checked related issues?

• [X] I have cross-checked this overview https://github.com/monal-im/Monal/issues/322 as well as filtered for related labels https://github.com/monal-im/Monal/labels

Describe your feature

The title says it all: replace the old and ugly share sheet UI with a modern an polished SwiftUI version but provide the same functionality.

[NafSyed]

Hey, I would like to work on this with you!!

[thevaidik]

You can't directly commit and push in main repo. Fork it and raise a pull request.

[tmolitor-stud-tu]

Hey, I would like to work on this with you!!

No, please improve your skills significantly and come back afterwards.