Fix SCM macro usage of refspec, branches

- fix ignored refspec SCM parameter (hardcoded to empty string):
  s/refspec: ''/refspec: '$GERRIT_REFSPEC'/g
- fix IEC SCM configuration regression (broken in previous commit):
  s/branches: '$GERRIT_BRANCH'/branch: 'GERRIT_BRANCH'/g
- add missing lf-infra-parameters macro to bluval job;
- use lf-infra-gerrit-scm macro in IEC templates (now that submodule
  recursive cloning parametrization is supported);
- retire 'validation-job-parameters' parameters macro, which is only
  an alias for 'lf-infra-parameters';
- rework validation SCM handling for refs/tags/...;

JIRA: VAL-103

Change-Id: I94957fb02afdfe8a01330e768dc5fde15f5ea05d
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>