Pass options to save_photon_hdf5()

[tritemio]

Currently is not possible to pass options to phconvert save_photon_hdf5().

We could add a 4th optional positional argument to the phforge script to pass a options.yaml which can contain any keyword arguments.

The advantages of using a YAML file for the these options instead of command line flags are:

1. Automatically accept all keyword arguments (i.e. if a new argument is added to save_photon_hdf5() phforge does not need to be modified to use it.
2. Easier to write for humans & computers
3. Possible to pass arguments containing a dictionary using same YAML syntax (instead of writing/generating python-syntax dictionary)
4. Easier to implement: the YAML file is loaded directly into a dictionary which is passed to save_photon_hdf5 with ** unpacking.