Trigger data should pass through MongoDB

[JelleAalbers]

Currently the trigger data is just dumped to an hdf5 file. This is not readable while the run is ongoing.

We should make a separate trigger data database in mongo, with a collection for each run, where this data can temporarily reside. After the run has ended the contents should be dumped to a file, so the analyst can find it along with the ordinary raw data (zipped bson). The trigger data can then be deleted from Mongo (if it takes up a lot of space, otherwise we can just keep it a while so people can continue to browse).

[JelleAalbers]

Implemented in #347