Fix documentation and source code links
Fix documentation and source code links

This patch update several links on Documentation. They were broken due
to renaming readme.md to README.rst.
Also this patch replaces outdated "stackforge" name on "openstack" in urls.

Change-Id: Ide4515f223d0f7884d5662b7365c411c09965343

stackforge/apps-catalog,stackforge/apps-catalog,stackforge/apps-catalog,stackforge/apps-catalog