Update getting started with credential crypto
Update getting started with credential crypto

We encrypt the sensitive information in the database now. This updates
the Getting Started guide to generate an encryption key.

Change-Id: I44a96302e736997a747f82c9d23006425396633f
Signed-off-by: Tomas Sedovic <2bc6038c3dfca09b2da23c8b6da8ba884dc2dcc2@sedovic.cz>

steveb/heat,pshchelo/heat,pshchelo/heat,cryptickp/heat,citrix-openstack-build/heat,rdo-management/heat,pratikmallya/heat,jasondunsmore/heat,miguelgrinberg/heat,Triv90/Heat,cwolferh/heat-scratch,openstack/heat,steveb/heat,gonzolino/heat,varunarya10/heat,takeshineshiro/heat,pratikmallya/heat,openstack/heat,cryptickp/heat,redhat-openstack/heat,maestro-hybrid-cloud/heat,NeCTAR-RC/heat,varunarya10/heat,Triv90/Heat,noironetworks/heat,dragorosson/heat,JioCloud/heat,gonzolino/heat,srznew/heat,noironetworks/heat,cwolferh/heat-scratch,ntt-sic/heat,redhat-openstack/heat,rdo-management/heat,rickerc/heat_audit,dragorosson/heat,dims/heat,NeCTAR-RC/heat,miguelgrinberg/heat,JioCloud/heat,rickerc/heat_audit,rh-s/heat,jasondunsmore/heat,ntt-sic/heat,maestro-hybrid-cloud/heat,takeshineshiro/heat,citrix-openstack-build/heat,srznew/heat,rh-s/heat,dims/heat,Triv90/Heat