Initial integration of providers via API:
- Generic views and modifiers for provider/server selection
- Add in OpenVPNView
- Prepare in WireGuardView
Also:
- Introduce ProfileProcessor, move IAP processing there
- Move .asModuleView() to ModuleViewModifier for proper animation
- Use .themeModal() rather than .sheet()
Also, fix SwiftUI not refreshing when remote profiles are updated. There
was no objectWillChange nor Published around
ProfileManager.allRemoteProfiles, and ProfileRowView was not treating it
as ObservedObject.
Closes#673
Davide