Move tree-diff dependency to tests together with all instances

[jasagredo]

Description

tree-diff uses GPL license so it should not be in the non-testing code in our case. This PR moves all the instances to the test packages so that only when testing this dependency is pulled in. See how when requesting to build just the libraries, no tree-diff is pulled from hackage:

cardano-ledger [ master][✘»!+?][λ 9.6.3]
❯ cabal clean

cardano-ledger [ master][✘»!+?][λ 9.6.3]
❯ rm -rf ~/.cabal/store/ghc-9.6.3/tree-diff-*

cardano-ledger [ master][✘»!+?][λ 9.6.3]
❯ cabal build cardano-ledger-shelley:lib:cardano-ledger-shelley cardano-ledger-byron:lib:cardano-ledger-byron cardano-ledger-allegra:lib:cardano-ledger-allegra cardano-ledger-mary:lib:cardano-ledger-mary cardano-ledger-alonzo:lib:cardano-ledger-alonzo cardano-ledger-conway:lib:cardano-ledger-conway cardano-ledger-babbage:lib:cardano-ledger-babbage cardano-ledger-api:lib:cardano-ledger-api set-algebra:lib:set-algebra cardano-crypto-wrapper:lib:cardano-crypto-wrapper cardano-data:lib:cardano-data cardano-ledger-binary:lib:cardano-ledger-binary vector-map:lib:vector-map small-steps:lib:small-steps non-integral:lib:non-integral --dry-run
Build profile: -w ghc-9.6.3 -O1
In order, the following would be built (use -v for more details):
 - non-integral-1.0.0.0 (lib) (first run)
 - small-steps-1.0.0.0 (lib) (first run)
 - vector-map-1.0.1.0 (lib) (first run)
 - cardano-ledger-binary-1.2.1.1 (lib) (first run)
 - cardano-data-1.1.2.0 (lib) (first run)
 - cardano-crypto-wrapper-1.5.1.0 (lib) (first run)
 - set-algebra-1.1.0.1 (lib) (first run)
 - cardano-ledger-byron-1.0.0.4 (lib) (first run)
 - cardano-ledger-core-1.10.0.0 (lib:internal) (first run)
 - cardano-ledger-core-1.10.0.0 (lib) (first run)
 - cardano-ledger-shelley-1.9.0.0 (lib:internal) (first run)
 - cardano-ledger-shelley-1.9.0.0 (lib) (first run)
 - cardano-ledger-allegra-1.2.5.1 (lib:internal) (first run)
 - cardano-ledger-allegra-1.2.5.1 (lib) (first run)
 - cardano-ledger-mary-1.4.0.1 (lib) (first run)
 - cardano-ledger-alonzo-1.6.0.0 (lib:internal) (first run)
 - cardano-ledger-alonzo-1.6.0.0 (lib) (first run)
 - cardano-ledger-babbage-1.6.0.0 (lib:internal) (first run)
 - cardano-ledger-babbage-1.6.0.0 (lib) (first run)
 - cardano-ledger-conway-1.12.0.0 (lib:internal) (first run)
 - cardano-ledger-conway-1.12.0.0 (lib) (first run)
 - cardano-ledger-api-1.8.0.0 (lib) (first run)

The PR is very verbose, but consists just of moving things around and exporting some internal constructors so that GHC can derive the instance in a separate module.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated. If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages. New section is never added with the code changes. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[lehins]

I am in favor of moving the instances, however the way cabal files were adjusted is totally wrong

[lehins]

There was a bunch of unnecessary adjustments to bounds of dependencies, mostly for *-test packages, but other than that this PR is beautiful. Thank you for doing all this work!!!!

[lehins]

Amazing stuff! Thank you for doing this! 👍