still TODO: check examples, outsourcing virtual environments

tidy up
ran tests

* Apply rules w.r.t. prompts and code blocks
* Restructure sections

big_data_frameworks.md.

* Restructure sections
* Unifiy writing style
* Unifiy code blocks

https://www.scads.de/transfer-2/beratung-und-support-en/.

Disable MD014/commands-show-output, rational does not hold anymore.

* Remove trailing whitespaces
* Resolve tabs to spaces

big_data_frameworks.md.