AliRelVal: multiple sections in config file
AliRelVal: exit with success after refresh
AliRelVal: do not accept jobs becoming NOT_RUNNING

Previously, in case of errors, a RUNNING job could become NOT_RUNNING
again and being therefore retriggered for validation. Now, if a job is
RUNNING, only DONE_OK and DONE_FAILED are accepted as new statuses.
AliRelVal: notification emails
AliRelVal: added a dry run mode

The "dry run" mode does not:
 - change the database
 - change the content of the filesystem
 - start the validation

It still does:
 - query the validation
 - send emails
Merge branch 'feature-alirelval-mail' into feature-alirelval