Should encapsulate scripts/ci better

There are a few things we could do to make the CI scripts better to test and functionality more re-usable:

1. It would be good that every environment variable required inside those commands is read from the command-line interface. That would give the chance for a user to test these recipes on their local installation before pushing changes
2. The deployment of artefacts (conda packages and documentation) could be better encapsulated into functions that are more re-usable. Then, apply DRY where it matters!