(Cleanup of #944) generic squonk job configuration as backend feature

[phraenquex]

Place-holder, so we discuss: did ticket #944 address the full scope of this ticket? The ticket activity shows only frontend work, but the original conversation mentioned backend and squonk-side work too.

@matteoferla is reviewing.

[matteoferla]

Here is my example of a possible way of implementing a Fragalysis–Squonk adaptor to deal with different options and abstracting away from the content-creator the need to understand the intricacies of both and allowing changing the RHS specs to change without breaking the stack:

https://github.com/matteoferla/Idea-for-Fragalysis-job-modularization