Speedup with parallel mars requests

[gisi90]

No description provided.

[joernu76]

a) There was an ancient PR, which wasn't merged. Sorry, I assumed you'd press the button. This causes now conflicts.
b) I assume this is way faster in processing. However, I am very unhappy w.r.t. to maintainability. The copy-pasting of all the shell-scripts gives fast results, but may cause a lot of issues at a later point in time, when changes have to be applied to a dozen places, instead of one central point.
We can put it here as it is, but not as the main-branch, which should more serve as a simple-to-understand exemplary flow.
Yours is an operational flow, which is necessarily more complicated.