Create an empty state for Admin / User / Groups screen.

Problem

Currently the empty state for this screen is not "standardized" to other screens's empty states.

Groups and projects
Populated:

Proposal

• Update screen to https://gitlab-org.gitlab.io/gitlab-ui/?path=/docs/regions-empty-state--no-illustration#no-illustration.
• Link should go to relevant docs page: https://docs.gitlab.com/ee/user/project/members/index.html

Updated groups and projects