This is a multi-part change to add BoringTun dependency to the
brave-core, to be used later in the VPN 2.0 architecture by a
privileged helper on desktop OSes. The dependency is added to
the existing VPN to ensure it actually gets built with the
browser, but not yet distributed.
Part 1: the license fix ensures that all the subsequently
vendored crates are properly processed by the license checker.
It also adds the entire "boringtun" directory to the list of
exclusions because we are not distributing BoringTun yet.
We will remove the directory from the exclusions in a separate
change once we are ready to distribute.
Alex
8ae6f1feb7