Caching of gprofiler queries

[bschilder]

Is your feature request related to a problem? Please describe. gprofiler queries can take a while, and this compounds when you need to make the same query multiple times. Intermittent internet access can also make this process inconsistent.

Describe the solution you'd like Speed up subsequent queries to gprofiler API by caching API results locally. I've done something similar recently in a python package by encoding the unique input gene set and the target database as a md5 hash.

Describe alternatives you've considered I requested the gprofiler team to enable the creation of a local database, instead of making live API calls.

Additional context Relates to #42