Resolve some flickering and state inconsistency due to overextended
observation of VPNProviderManager. Narrow down its scope to
VPNProviderServerView.
The downside of that, for now, is that servers are loaded "lazily late",
but this flow will make region selection from home easier.
Finally, show filters in popover on iPad.
Improve rendering and work around some SwiftUI bugs, e.g. with .menu
Picker on iOS (use .navigationLink instead).
Here goes the hierarchy bottom-up:
- ProviderPicker: a Picker wrapper built around ProviderManager
- ProviderContentModifier: adds a ProviderPicker on top and replaces the
content with a set of provider selectors when a provider is selected
- VPNProviderContentModifier: wrapper for ProviderContentModifier that
adds a VPN server selector
- OpenVPNView: provides a view of specific OpenVPN settings, and adds a
credentials selector to the provider/server selectors provided by
VPNProviderContentModifier
Davide