Adjust for karaf 4 not happening in carbon

Adjust for karaf 4 not happening in carbon

1) Add projects distribution check job for k3 in nitrogen:
(to remove after the migration)

{project-name}-distribution4-check-carbon ->
{project-name}-distribution3-check-nitrogen

2) Add distribution verify jobs for k3 in nitrogen:
(to remove after the migration)

distribution4-deploy-carbon -> distribution3-deploy-nitrogen
distribution4-offline-carbon -> distribution3-offline-nitrogen
distribution4-check-carbon -> distribution3-check-nitrogen

3) distribution test jobs will run on k3 in nitrogen:
(autorelease can override this when it produces k4 distro):

integration-distribution-test-{stream}
integration-sanity-test-{stream}
integration-distribution-weekly-test-trigger-{stream}

4) Projects can start premature test for k4 in nitrogen:
(to remove after the migration):

{project}-csit4-1node-{functionality}-{install}-carbon ->
{project}-csit4-1node-{functionality}-{install}-nitrogen

Change-Id: If2e7d12d2721f293119cd36c4ec3f1f3e539710c
Signed-off-by: Luis Gomez <ecelgp@gmail.com>