cet-is

In the recent release of art, we now can set the trigger bits of each given path, BUT the bits sequence has to be contiguous, in order to keep trigger_paths dense. The request is to allow trigger_paths to be non-dense. In this way, we can set arbitrarily the bits to the various paths.
This feature is especially useful for the Mu2e case because when we will be in data-taking mode, the Trigger Menu might change from Run to Run, thus having the possibility to keep the same trigger_bit to the same paths would immensely simplify the bookkeeping and the operations downstream needed to handle/process the data.