Draft: Add jitter, phasemask and custom pupil from .ini

Jitter has already been added but there is no keyword from the .ini file to setup the jitter in mas at the moment.

• Consider setting jitter from config.keys()
• Add a class attribute called 'jitter' in either the system or ParametricPSFfromPSD to call self._otfJitter in the psfmodel.py

Same for the custom pupil and phasemask

• Consider setting the path of the pupil and the phasemask from the config.keys

requested review from @rfetick

assigned to @alexislau