fix(docs/reference): fix broken links in reference guide

A couple of changes in this PR:

- gave each client reference an internal link
- fixed up `client/builds` and `client/releases` to what they should actually reflect
- removed shortcuts from client ref (they were redundant, could possibly be added back as `client/shortcuts`?)

#1190 partially relies on this PR, as the internal link to `deis builds` is broken without it.