Move see also blocks to bottom of each page to include reading docs, remove 'fork me' to avoid text overlap,
simply menu nav so folks find the chapter link.

Added documentation on the 'file' module and how 'copy' and 'template' can also use the options that 'file'
provides.

Added documentation on the 'shell' module, which is a virtual module and isn't really in the library folder.
Docs build.

Updating docs, added extensive info on playbook async + external vars_files for keeping variables outside of
the playbook file.