add kraken2 to seqinspector

[FranBonath]

[ctuni]

The PR is passing all tests and ready for review 🥳

[FranBonath]

Since this is ready to review and we do want to have kraken 2 as an option after the V1 release, I am leaving this here. Maybe someone can pick it back up during the hackathon.
OBS! this will not be in the V1 release!

[ctuni]

Great! Last time I checked the PR was working and passing tests, but I don't expect this to be the case any more 😅 Maybe it will need some tweaks, I'll resolve some conflicts now so it's easier to review and merge!