Add name to the setup group

[tritemio]

I though it may be convenient to add a name (string) field to the setup group.

A name will make easier identifying measurements files from different setups, especially if they don't have a measurement_specs group.

[tritemio]

Maybe postpone or reject this?

[harripd]

As v0.5 (maybe 0.6 now if we include FLIM) is putting more information about detectors etc. into the setup group, I think the is is a good idea, but I would rename it measurement_type to stay consistent with naming from measurement_specs.

[smXplorer]

There is already a measurement_type field in /photon_data/measurement_specs, see https://photon-hdf5.readthedocs.io/en/0.5.dev/phdata.html#measurement-specs

Looking at the description of the setup group, https://photon-hdf5.readthedocs.io/en/0.5.dev/phdata.html#measurement-specs, it is clear that a "name" for it would be something like "YH 2002G" or "Single-spot usALEX setup". This is not the same as a "measurement type", I believe (many different types of measurements can be performed on the same setup).