Provide basic but hopefully useful man page.
shell.rst was merged into and replaced by the man page in HTML docs.
pbr is used to determine version.
Docs copyright was changed to more accurate "OpenStack Contributors".
Fixes: bug 1206968
Implements: blueprint clients-man-pages
Change-Id: Iedd7b4b161ced564833fd9433762b87a4c1a374d
