Is aws_tower config superfluous?

[adamrtalbot]

Do we need the aws_tower config? It just appears to set the executor which isn't necessary in Tower. Can we remove it @ggabernet?

[apeltzer]

I think it is, yes.

[maxulysse]

It is still used in https://github.com/nf-core/demultiplex, but yes, it's mostly superflous, I'm going for a suppression.