SaaS User Cap feature
## Closing Notes
Closing this issue as user caps for SaaS was [rolled out to all namespaces](https://gitlab.com/groups/gitlab-org/-/epics/9263#note_1507490814) and no longer requires an activation request
[Here’s the documentation](https://docs.gitlab.com/ee/user/group/manage.html#user-cap-for-groups) that you can share with the customer and the [known limitations.](https://docs.gitlab.com/ee/user/group/manage.html#known-issues)
2nd iteration enhancements in this epic: https://gitlab.com/groups/gitlab-org/-/epics/6863
## Summary
In https://gitlab.com/groups/gitlab-org/-/epics/4315, we introduced a `User Cap` setting for self-managed admins to prevent accidental user overages.
This is the next iteration of this feature to bring the setting to SaaS Group owners as well.
## Success Criteria
The `User Cap` setting for SaaS should operate the same as the behavior for self-managed however we are treating the instance-level setting/behavior for SaaS at the root namespace instead. See [designs](https://gitlab.com/gitlab-org/gitlab/-/issues/321934/)
1. [ ] Provide Group owners with the ability to set a User Cap as described in https://gitlab.com/groups/gitlab-org/-/epics/4315#feature-characteristics (noting self-managed admin = Group Owner in SaaS)
1. [ ] Alert group owners when the limit has been reached
1. Only applicable to root group owners
1. Should display on all pages within namespace
1. Should be dismissable
1. [ ] Put members into pending state once limit is reached
1. [ ] Send email notification to group owner once limit is reached
1. [ ] Ensure the Approval of adding a member from Pending state is tracked in the Audit Logs
The actions listed here can be broken into multiple issues and/or MRs as determined by the dev who picks this up.
## Designs
https://gitlab.com/gitlab-org/gitlab/-/issues/321934/
## Feature Flag
Features related to this epic will be implemented under the `saas_user_caps` FF (group-level feature flag).
- `saas_user_caps` FF rollout issue: https://gitlab.com/gitlab-org/gitlab/-/issues/336251
Please be advised that SaaS User Caps will not rollout to production for all users. Instead, this feature will be enabled as it is negotiated into the contract. As an MVC process, the sales rep will notify me (or Utilization PM) when a deal includes this feature, then we will ask engineering to release the feature for the single root group. In the future, we can create an automated provisioning process.
epic