Support conversion of bbo and stamp at same time

[blcham]

Currently, we can convert bpmn exclusively only to bbo or stamp. We would like to be able to do same.

Suggested CLI params:
--output-stamp-file / -ostamp $FILE
--output-bbo-file / -obbo $FILE
--output-file -- this could be used only if only one transformation bbo | stamp is used

All of the above CLI params should be optional as there should be a convention how the output file names are generated from input file names. Suggested output file names could be:

• for stamp: ${bmpn_file}-prestamp.ttl
• for bbo: ${bmpn_file}-bbo.ttl

[grigobog]

implemented in https://github.com/kbss-cvut/bpmn2stamp/releases/tag/0.03

[blcham]

@grigobog
Not really sure how it works :(, but it is not very good practice that you will explain me here or that i start reading code too much ...
i created ticket #9