Chore: Move to centos8-builder

Chore: Move to centos8-builder

jjb/optf/optf-osdf.yaml
jjb/policy/policy-apex-pdp.yaml
jjb/policy/policy-api.yaml
jjb/policy/policy-clamp.yaml
jjb/policy/policy-common.yaml
jjb/policy/policy-distribution.yaml
jjb/policy/policy-docker-base-common.yaml
jjb/policy/policy-drools-applications.yaml
jjb/policy/policy-drools-pdp.yaml
jjb/policy/policy-gui.yaml
jjb/policy/policy-models.yaml
jjb/policy/policy-pap.yaml
jjb/policy/policy-parent.yaml
jjb/policy/policy-xacml-pdp.yaml
jjb/relman/relman.yaml

Issue-ID: CIMAN-33
Signed-off-by: Bengt Thuree <bthuree@linuxfoundation.org>
Change-Id: Iad21df45bc80e1a4cbd77066a46a4f80f57ae5d8