added Twist and Arbor capture types

[stschiff]

I've just added the capture types discussed on Slack, plus the new Twist capture reagent. I've opted to call this TwistAncientDNA following this preprint

[nevrome]

Note that this change has (off the top of my head) at least the following consequences:

• A new release of the schema has to be published
• The documentation on the website and the schema-software reference version list has to be updated
• poseidonR has to be updated (easy: just run the script in data-raw)
• poseidon-hs and all it's reverse dependencies have to be updated (easy: just add the constructors and update the instance definitions)
• All packages in the public repo have to be updated (easy: trident update)

Not difficult, but we have to remember to do all these things as soon as this is merged.

[stschiff]

Yes, OK. I will look into these todos and make sure they get added as issues once I merge this.

[nevrome]

I fear it's not enough to add these things as issues. In my opinion there should already be PRs ready. Happy to take over some of these ToDos.

[nevrome]

Very important addition to the ToDo list: We also need a tool to automatically update packages from 2.5.0 to 2.6.0. Should not be difficult.

[stschiff]

I have just moved the edits in this PR over to #51. I will close this.