move strandedness in params

[daler]

Currently, strandedness is handled on a per-tool basis, and is handled inside the rule body. However, if the config entry for strandedness changes, this does NOT trigger a re-run of rules that use that config option -- because the body of the rule didn't change.

It would be nice to have rules re-run if strandedness is updated. One way of doing this would be to move strandedness to the params: directive so the snakemake --rerun-trigger would detect the param changes.