This provides canonical BUILD formatting and puts protoxform in charge
of being able to determine import paths, without having to worry about
Bazel implications.
Part of #8082.
Risk level: Low
Testing: tools/proto_sync.py, visual inspection of diffs.
Signed-off-by: Harvey Tuch <htuch@google.com>
Mirrored from https://github.com/envoyproxy/envoy @ e53f40f0e5ccc84fca5cd350416fe0f2accf8229