Merge branch 'acl-hacks' into 'collabora/master'

docs/api/api/obs.rng

docs/api/api/project.rng

src/api/app/controllers/source_controller.rb

src/api/app/models/allowbuilddep.rb

src/api/app/models/project.rb

src/api/app/views/models/_project.xml.builder

src/api/db/migrate/20191011000000_create_allowbuilddeps.rb

src/api/db/structure.sql

src/backend/BSSched/Access.pm

src/backend/BSXML.pm

src/backend/bs_srcserver