Statistics about amount of clusters configured
What does this MR do?
GitLab should reports about setup used for Gitaly.
Now it reports about amount of Praefect clusters configured.
Usual Gitaly setup with multiple storages will report none clusters used,
but setup with Praefect with multiple Gitalies behind will report amount of such Praefects as clusters.
Related to: gitaly#2664 (closed)
Support of the new metric in version-gitlab-com
Does this MR meet the acceptance criteria?
Conformity
Edited by Pavlo Strokov