Adjust CSIT for unified review verification

 - enable use of locally built images (without nexus repo prefix)
   in docker-compose.yaml
 - use local docker images in CSIT by default
 - remove forced docker image push of odlsli-alpine and dgbuilder
 - remove unique docker tag usage
 - this change requires https://gerrit.onap.org/r/c/ci-management/+/116920
   to be merged to work correctly

Issue-ID: INT-1823
Signed-off-by: Lasse Kaihlavirta <l.kaihlavirt@partner.samsung.com>
Change-Id: Ibc391ef4fc9412665a26486af6fcc8c26096cc64