personalization: implement reading back values from a PES
Implement get_values_from_pes(), the reverse direction of apply_val(): read back and return values from a ProfileElementSequence. Implement for all ConfigurableParameter subclasses.
Future: SdKey.get_values_from_pes() is reading pe.decoded[], which works fine, but I07dfc378705eba1318e9e8652796cbde106c6a52 will change this implementation to use the higher level ProfileElementSD members.
Implementation detail:
Implement get_values_from_pes() as classmethod that returns a generator. Subclasses should yield all occurences of their parameter in a given PES.
For example, the ICCID can appear in multiple places. Iccid.get_values_from_pes() yields all of the individual values. A set() of the results quickly tells whether the PES is consistent.
Rationales for reading back values:
This allows auditing an eSIM profile, particularly for producing an output.csv from a batch personalization (that generated lots of random key material which now needs to be fed to an HLR...).
Reading back from a binary result is more reliable than storing the values that were fed into a personalization. By auditing final DER results with this code, I discovered: - "oh, there already was some key material in my UPP template." - "all IMSIs ended up the same, forgot to set up the parameter." - the SdKey.apply() implementations currently don't work, see I07dfc378705eba1318e9e8652796cbde106c6a52 for a fix.
