* build(github): add common 'labels.json'; update release drafter config
As discussed in the org meeting we aim for consistency in the labels
used on the engine and in modules. This PR adds the common configuration
to `.github/labels.json`, which can be used to sync labels with
https://github.com/Financial-Times/github-label-sync
Co-authored-by: jdrueckert <jd.rueckert@googlemail.com>