Implement HLT beamspot update test

Re-implement the beamspot udpate test using a local sqlite file. Since we lost the ability of using event modifiers in athenaHLT, it's now a two-step process of first creating a dedicated bytestream file and then running athenaHLT using a new python algorithm that takes care of writing a new beamspot to the sqlite file at the appropriate time.

An ART build test for this has been added as well.