Setup heat-admin instead of ec2-user

Heat instructs cloud-init to setup ec2-user by default, we need heat-admin.
Set a default FACTER_heat_db

This is used to set a default in heat.conf during image build.
Install kernel-modules-extra

This prevents kernel-debug-modules-extra getting installed (It gets
pulled in as a dep to gfs2-utils which has Requires: kernel-modules-extra)
Pass metadata, waitcondition, and watch server urls to heat-engine