feat(oauth): implement OAuth2 helper package

mentioned in commit 77d3b1ae

mentioned in merge request gitlab-org/cli!2211 (merged)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2576 (merged)

mentioned in merge request gitlab-org/cli!2212 (closed)

mentioned in merge request gitlab-com/gl-infra/woodhouse!660 (merged)

mentioned in merge request gitlab-org/release-tools!4304 (merged)

mentioned in merge request fforster/gitlab-mcp!111 (merged)

mentioned in merge request schober-server/kubernetes/images/gitlab-token-refresher!18 (merged)

mentioned in merge request gitlab-com/gl-infra/autolabels!68 (merged)

mentioned in merge request gitlab-com/gl-infra/ringctl!321 (merged)

mentioned in merge request gitlab-com/gl-infra/platform/runway/runwayctl!1053 (merged)

mentioned in merge request gitlab-org/container-registry!2386 (merged)

mentioned in merge request ydkn/gitlab-runner-cleanup!40 (closed)

mentioned in merge request fforster/epic-update!12 (merged)

mentioned in merge request sue445/tanuki_reminder!254 (merged)

mentioned in merge request sue445/create-merge-request!138 (merged)

mentioned in merge request gitlab-com/gl-infra/oncall-robot-assistant!104

mentioned in merge request hojerdev/git-sync!64 (merged)