Enable selection of multiple groups, subgroups/projects on cycle analytics

Problem to solve

Users might work across groups, subgroups and projects, so they should be able to select a combination of these in order to see cycle analytics. This is effectively moving Cycle Analytics to instance level after https://gitlab.com/gitlab-org/gitlab-ee/issues/12078. Please refer to https://gitlab.com/gitlab-org/gitlab-ee/issues/12688 for the description/UX since it's the same.

Intended users

EMs, PMs

Further details

Proposal

Permissions and Security

Documentation

Testing

What does success look like, and how can we measure that?

What is the type of buyer?

Links / references