There was duplication and a ugly `#if os(macOS)` with some footers
explicitly rendered on macOS with .themeFooter() (now .themeSubtitle()).
Move this logic to the .themeSection() modifiers by adding a
`forcesFooter` parameter. When true, a fake footer is added on macOS as
the last row of a section.
Let the AppCoordinator take care of the connection requirements via
modals:
- onInteractiveLogin() - now presented on AppError
- onProviderEntityRequired()
- onPurchaseRequired()
- Any other connection error
Subviews must not use tunnel.connect(), rather they route connection
requests via the ConnectionFlow callbacks. In particular, migrate to the
AppCoordinator the connection logic from:
- TunnelToggleButton.perform()
- ProviderEntitySelector.onSelect()
onInteractiveLogin() and onPurchaseRequired() are now handled
internally, while onProviderEntityRequired() is kept public because it's
how subviews may present the entity selector.
Extras:
- Avoid modals overlap with a 500ms delay
- Shrink interactive login size on macOS
Some providers require specific credentials for OpenVPN, different from
account credentials. Update the API index with this information to show
an information footer and possibly a link to the OpenVPN credentials.
Also, fix the OTP footer not appearing on macOS.
