Deprecate AauxiliaryDataHash

[lehins]

Description

This is PR adds TxAuxDataHash and deprecates AauxiliaryDataHash in its favor, because it does not follow the naming convention that we use for the rest for the types

Besides that a couple of other cleanup actions:

• Extract hashTxAuxData into a standalone function, since all current eras have and future eras will have the same imlpementation.
• Extract indexProxy out of HashAnnotated type class and deprecate it as useless.

Checklist

• Commits in meaningful sequence and with useful messages
• Tests added or updated when needed
• CHANGELOG.md files updated for packages with externally visible changes
  
  New section is never added with the code changes. (See RELEASING.md)
• Versions updated in .cabal and CHANGELOG.md files when necessary, according to the
  versioning process.
• Version bounds in .cabal files updated when necessary
  
  If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• Code formatted (use scripts/fourmolize.sh)
• Cabal files formatted (use scripts/cabal-format.sh)
• hie.yaml updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[teodanciu]

Looks good to me, just some trivial remarks.