Refresh README and its docs links
Refresh README and its docs links

The current README still mentions EC2 and over-duplicates information
that now lives in other files, like CONTRIBUTING.rst.

This patch re-focused the README on three key groups of folks:
* API users
* Operators
* Developers

Change-Id: I9df445ca0c800f0985900dcb00466c15e8d5570f

gooddata/openstack-nova,rajalokan/nova,mikalstill/nova,klmitch/nova,vmturbo/nova,rajalokan/nova,Juniper/nova,mahak/nova,openstack/nova,mikalstill/nova,sebrandon1/nova,rahulunair/nova,Juniper/nova,jianghuaw/nova,hanlind/nova,gooddata/openstack-nova,mikalstill/nova,jianghuaw/nova,phenoxim/nova,sebrandon1/nova,hanlind/nova,jianghuaw/nova,jianghuaw/nova,vmturbo/nova,rahulunair/nova,cloudbase/nova,cloudbase/nova,openstack/nova,rajalokan/nova,klmitch/nova,hanlind/nova,klmitch/nova,klmitch/nova,Juniper/nova,cloudbase/nova,alaski/nova,vmturbo/nova,vmturbo/nova,gooddata/openstack-nova,gooddata/openstack-nova,alaski/nova,rajalokan/nova,rahulunair/nova,phenoxim/nova,Juniper/nova,sebrandon1/nova,mahak/nova,mahak/nova,openstack/nova