feat(groups): add support for merge related settings

mentioned in commit 47db54d6

mentioned in merge request gitlab-org/cli!2695 (merged)

mentioned in merge request gitlab-com/gl-infra/platform/runway/runwayctl!1458 (merged)

mentioned in merge request sickit/token-operator!47

mentioned in merge request gitlab-com/gl-infra/woodhouse!738 (merged)

mentioned in merge request hojerdev/git-sync!72

mentioned in merge request gitlab-com/gl-infra/oncall-robot-assistant!110

mentioned in merge request schober-server/kubernetes/images/gitlab-token-refresher!37

mentioned in merge request fforster/epic-update!52 (merged)

mentioned in merge request fforster/gitlab-mcp!225 (merged)

mentioned in merge request gitlab-org/release-tools!4633

mentioned in merge request gitlab-com/gl-infra/autolabels!148 (merged)

mentioned in merge request gitlab-com/gl-infra/ringctl!429 (merged)

mentioned in merge request gitlab-org/cli!2697 (closed)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2848 (merged)

mentioned in merge request gitlab-org/container-registry!2717

mentioned in merge request kickr-dev/kickr!111 (merged)

mentioned in merge request kickr-dev/engine!44 (merged)

mentioned in merge request ydkn/gitlab-runner-cleanup!47