improving tool documentation & adding tests

[ewissel]

Description of feature

Hi nf-core team,

Some of the current documentation around tool usage for nf-core/funcscan is a bit ambigious, leading to confusion around parameter usage. For example, for flag --amp_hmmsearch_models, it is not clear that the database path should be in quotes, or for --bgc_hmmsearch_models, it is not clear where the database path needs to point (include subdirectories? full path to files with wildcard?).

Further, some of these tools have long run times or spit out meaningless error messages when the database path is different from what is expected. It'd be good to have some more internal tests here to make sure the path looks as expected. This is also discussed on the slack channel, so discussion can be found there.

Thanks for all the work you do to create and maintain this workflow.