Adds template for adding Gitaly storages
For woodhouse!283 (merged) this relocates the Gitaly storage creation template to the production tracker so it can be used as a template for Change Management.
Part of https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24229
Note: this lifts the old template into the gl-infra/production
as-is, we intend to update it later once we go through the full process in https://gitlab.com/gitlab-com/gl-infra/production/-/issues/16120
Edited by John Jarvis