Add Onionoo's build revision to documents
Documents will contain a build_revision field, if a revision could be determined, e.g.,
{"version":"4.1","build_revision":"abcdfe7","relays_published":"2017 ...Cf. #21414 (moved) for the discussion and the changes already available in metrics-base.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information