feat: add support for cloud execution

[CJ Herrmann]

Is your feature request related to a problem? Please describe.

@fgypas : Since snakemake has cloud execution capabilities, we can relatively easily support such environments (e.g. kubernetes). Do we want to go in that direction?

Describe alternatives you've considered

@uniqueg : ELIXIR Cloud AAI is working on a Snakemake WES, Snakemake TES backend and support for Snakemake in the CWLab portal. With a few months down the road, this will probably be solved generically for any Snakemake pipeline. We could actually speed this up by helping the German ELIXIR node a bit with this. Both TES backend and WES should be pretty easy to do. With TESK and Funnel that would allow us to basically execute on every cloud and HPC environment...