Merge topic 'contribute-through-gitlab'

140357ea CONTRIBUTING: Document contribution through the Kitware GitLab Instance
56b707dd README: Add section about reporting bugs
33f828d4 README: Convert from `.txt` to `.rst` markup
5f206c3a Tell Git to use a distinct conflict marker size in `.rst` files
17a1200c Convert developer setup scripts away from Gerrit Code Review
41a7fe5b Add pre-commit hook to check whether SetupForDevelopment must re-run

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Ben Boeckel <ben.boeckel@kitware.com>
Merge-request: !1