Extend the feature by also providing a complementary "include" policy,
i.e. activate the VPN _only_ on the specified networks. "Trusted
networks" was only providing the "exclude" counterpart, i.e. _except_
the specified networks.
Closes#119
On configuration error, retain information about the profile that
triggered the error. For now, present an alert, but with this
information the UI can be easily changed later.