Status allows for importing communities via their private keys.
There's a requested feature that users should be able to import a community via
its public key as well.
This will behave differently as private keys won't give users ownership
of the communities. When importing via a (compressed) public key, Status
will try to fetch information about the community from the network. If it
finds such information, it'll load it into the app and create
a communitiy view from which users can then request access.
If it can't find a community or community information in the network,
the user will get a dedicated error message.
This commit also refactors the `ImportCommunityPopup` such that it uses
`StatusDialog` and updates the copy accordingly since importing via
public key is now possible as well.
Closes#8339
Alexandra Betouni
Igor Sirotin
Pascal Precht
Patryk Osmaczko
Boris Melnik