better document default effective settings related to gitlab.rb.template
It is hard to tell what the effective default settings of gitlab.rb
are despite #1694 (closed), !1070 (closed), !1135 (merged), and other related closed issues and MRs. Users keep getting pointed to https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/files/gitlab-cookbooks/gitlab/attributes/default.rb but it is not easy to tell from that file what the default settings are. For example, how can one easily tell if LFS is enabled by default and where LFS objects will be stored? https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/doc/package-information/defaults.md is a start but incomplete.