PR3: Tweaks around inputs and outputs restructured, with an additional tweak

[mmontin]

This PR introduces a few changes around tweaks and outputs:

• A new tweak is introduced to modify certain spend redeemers based on their type
• Tweaks revolving around inputs, outputs and mint have been separated into their own files
• Tweaks revolving around tampering the datum have been put into output tweaks
• Outputs now have setters for their various fields

[florentc]

IMO This greatly improves the organization of the tweaks by fitting the same structure as a skeleton and its fields.

Since modifySpendRedeemersOfTypeTweak is, quite naturally, introduced in Tweak.Inputs, maybe the tweaks in TamperDatum should belong in Outputs from now on?

[yannham]

I like smaller files 🙂 nothing much to add otherwise.

[mmontin]

@florentc having the datum tampering in the outputs makes complete sense thanks for the suggestion. I'll add it right away in this PR.