messaging feature to start periodic tests once builds are done

Added script to receive the message about done builds and producing the file for the jenkins job launching the tests.

To send the message that the build is done, one can launch scripts/lbq-builddone specifying slot, project, platform and build id.

The message is consumed calling scripts/lbp-check-periodic-tests-msg with two arguments: config file of the periodic tests and name of the queue to store the messages., for example ./lbp-check-periodic-tests-msg ./LHCbNightlyConf/test_schedule2.xml -q JenkinsPeriodic. The script produces the file with the parameters for the jenkins/nightly-builds/tests.sh job in Jenkins.