Put technical reproducibility burden completely on authors

It is of course mainly the author's responsibility to come up with a workflow, but the current [community process](https://codecheck.org.uk/guide/community-process#codecheck-community-process-guide) implies that the reviewer could/should invest additional work to make things reproducible, e.g. by making the repository binder-ready, creating a Makefile (see issue #19), etc.
I think it would be better to clearly separate the responsibility: the author provides the workflow (binder, Rmarkdown or jupyter notebook, Makefile, shell script, README file with step by step instructions, ...) and all the CODECHECKER does is following/executing this workflow, verifying that it works and documenting the exact environment that was used. The last part would be something like `pip freeze`, `conda list` or R's `sessionInfo()`, i.e. not a format that allows to reproduce things exactly at the press of a button (you'd need the same platform, etc.), but could give valuable hints if future replications fail or give different results.