Simplify run_id readout

The current readout of the run_id is quite complicated:

For ORCA neutrino files:

• run_id in EventInfo is wrong (Aanet spits out 1 no matter which run due to wrong simulation output)
• no Header available
• run_id can be found in the RawHeader[0][1]

For ORCA mupage files:

• run_id in EventInfo is wrong
• no Header available
• run_id can be found in the RawHeader[1][0] (!!)

For ORCA random_noise files:

• run_id can be found in the EventInfo, and this time it's finally correct!

Cf. https://git.km3net.de/ml/OrcaSong/blob/master/orcasong/file_to_hits.py#L139.

Need to think about this.