Switched to using subdetector_to_string and subsystem_to_string methods

[bieryAtFnal]

…in hdf5_dump.py

I made use of Python integer-to-SourceID::Subsystem and integer-to-DetID::Subdetector conversion functions in recent changes to wib2decoder.py, and it seemed like the use of them in hdf5_dump.py would be useful. This PR has candidate changes in this regard.

Of course, if there were reasons for not using those conversion functions, we can skip this PR.

[dingp]

Is it worth to keep the current DETECTOR and SUBSYSTEM dictionary and only use them if daqdataformats and detdataformats python modules were not found? This maintains the ability to run the script outside of the DAQ development environment. Though I guess few people actually does this.

One of the concept when firstly designing hdf5_dump.py was it remains as an independent/external tool which only relies on "built-in" python modules. We can have a separate python module/script which leverages other package's python bindings/modules to decode the HDF5 data file.