[native] Add empty RegistrationNavigator & KeyserverSelection
Summary:
This diff adds the plumbing for RegistrationNavigator and KeyserverSelection, and makes the new registration button open it.
Depends on D7495
Test Plan:
| recording |
Reviewers: ginsu, atul
Reviewed By: atul
Subscribers: tomek
Differential Revision: https://phab.comm.dev/D7496