Moving the old release notes into the Reno releasenots tree broke
the embedded :doc: roles. Restore these using sphinx.ext.extlinks to
manage the URL to the OSC docs.
Add the following aliases:
* lpbug - generic Launchpad bug :lpbug:`123456`
* oscbp - OSC blueprints :oscbp:`Blue Print <bp-name>`
* oscdoc - OSC Docs :oscdoc:`Comamnd List <command-list>`
Change-Id: Iecfdd666d961c35f0ccb3b9f10df1d2620cb099f