Investigate the need for defining constants in nimi-python API

# Description of issue

In driver C APIs, there usually are constants defined to represent certain magic numbers. e.g. In nidigital, there is NIDIGITAL_VAL_ACQUIRE_ALL_SAMPLES (= -1), intended to represent capturing all available History RAM samples in FetchHRAMData() function.

There isn't a way to represent these magic number in nimi-python API. We should consider adding something similar.