Filling variables whose input comes from simtel and corsika

[nietootein]

Some of the metadata fields that are stored as attributes are currently not being filled, specifically:

• CORSIKA_ver
• E_max
• E_min
• prod_site_B_field
• prod_site_alt
• prod_site_array
• prod_site_coord
• prod_site_subarray
• simtel_ver
• spectral_index

These data can be found in the simtel history block, but retrieval of such a block through pyhessio/ctapipe has not been implemented (see this issue cta-observatory/pyhessio#52).

[morcuended]

I have been looking over pyhessio and ctapipe.io modules and I have managed to retrieve some of the required metadata already considered in pyhessio, at least those I could find easily. This is how it looks so far.

[bryankim96]

I tried to incorporate these new fields in c7bfcaf and bae7830, but it seems like this update to ctapipe may still be incomplete (see cta-observatory/ctapipe#655). For now they are included in the global metadata dict but I have it try/catch so it does not crash if they are not actually supported in the HDF5 event_source.