Move storage directory creation to gitaly recipe
Continuation from #2194 (closed)
Right now, gitaly is not a hard requirement for GitLab to work. One can simply turn off gitaly and GitLab will not blow up. Down the road, that will not be the case. When gitaly becomes a hard requirement, we can get rid of the confusing setup where storage directories are identified in a gitaly library while they are actually created in gitlab-rails recipe.
When gitaly is a hard requirement, move the storage directory creation to gitaly recipe.