Description of the problem, including code/CLI snippet

The Gitlab provides some general statistics via /application/statistics.
See https://docs.gitlab.com/ee/api/statistics.html

Expected Behavior

These data are available via gitlab.statistics().

Actual Behavior

Nothing.

Specifications

• python-gitlab version:
• API version you are using (v3/v4):
• Gitlab server version (or gitlab.com):