STY: improve bots/outputs/misp/output_api.py
STY: improve bots/outputs/misp/output_api.py

 * Refactor process() to call new _inset_misp_event() to keep the
 function short and more readable.

aaronkaplan/intelmq,aaronkaplan/intelmq,certtools/intelmq,certtools/intelmq,aaronkaplan/intelmq,certtools/intelmq