Use relative paths for group/project/user avatars

app/helpers/application_helper.rb

app/models/concerns/avatarable.rb

app/models/group.rb

app/models/project.rb

app/models/user.rb

...logs/unreleased/use_relative_path_for_project_avatars.yml

config/initializers/doorkeeper_openid_connect.rb

lib/api/entities.rb

lib/api/v3/entities.rb

spec/helpers/application_helper_spec.rb

spec/helpers/avatars_helper_spec.rb

spec/models/group_spec.rb

spec/models/project_spec.rb

spec/models/user_spec.rb

spec/requests/api/groups_spec.rb

spec/requests/api/v3/groups_spec.rb

spec/services/projects/participants_service_spec.rb