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 2: vendored crates that BoringTun depends on, plus some
ignore rules for linters to make sure builds are not broken;
following the similar ignores for wasm. There is also a
Cargo.lock file with the list of the dependencies and versions.
All the vendored crates were created by running `cargo vendor`;
the source files of the crates are unmodified, and DO NOT NEED
any manual review.
Alex
69539f1542