Cardano Updates

* Fix CHANGELOG entry for CDDL
* Add `Cardano.Ledger.Core.modifyTxAuxData` in order to be able to apply
  some function on the `txAuxData` field even when it is set to
  `SNothing`.

Add plain DecCBOR instances for DijkstraBlockBodyRaw and
DijkstraBlockBody (needed for decoder equivalence tests), and a
custom ToExpr instance for DijkstraBlockBody. Add block_body to
the CddlSpec test suite.

Co-authored-by: Alexey Kuleshevich <[email protected]>

Add plain DecCBOR instances for DijkstraBlockBodyRaw and
DijkstraBlockBody (needed for decoder equivalence tests), and a
custom ToExpr instance for DijkstraBlockBody. Add block_body to
the CddlSpec test suite.

Add plain DecCBOR instances for DijkstraBlockBodyRaw and
DijkstraBlockBody (needed for decoder equivalence tests), and a
custom ToExpr instance for DijkstraBlockBody. Add block_body to
the CddlSpec test suite.

Define HuddleRule instances for "block_body" and "peras_certificate"
in the Dijkstra era, with a custom CBOR generator for block_body
that generates valid transaction indices. Update the CDDL spec to
match the new block structure: block = [header, block_body].

Replace the manual segmented-witness serialization with MemoBytes,
which simplifies the code significantly. The block body is now
serialized as a flat 3-element list [invalid_transactions, transactions,
peras_certificate] instead of 5 separate segments.

Also fix PerasCert to encode/decode as bytes (matching CDDL),
reimplement alignedValidFlags using IntSet, and expose
DijkstraBlockBodyRaw/MkDijkstraBlockBody from Internal module.

Change genArrayTerm from Gen to MonadGen so it can be used in
CBORGen contexts (e.g. custom CBOR generators for Huddle specs).

- Add `blockBodySize` as a method on `EraBlockBody` with a default
  implementation using `EncCBORGroup`, replacing the standalone
  `bBodySize` function
- Remove `EncCBORGroup (BlockBody era)` superclass constraint from
  `EraBlockBody` so that eras can provide their own `blockBodySize`
  without needing `EncCBORGroup`

- Added blockBodySize method
- Added more CddlSpec tests
- Add BlockBody DecCBOR instance
- Fix PerasCert to encode/decode as bytes (matching CDDL nil / VBytes)
- Use encodeNullStrictMaybe/decodeNullStrictMaybe for optional peras_certificate
- Handle both definite and indefinite length lists in BlockBody decoder
- Add index range validation in BlockBody decoder (matching Alonzo)
- Add DecCBOR instances for DijkstraBlockBodyRaw and DijkstraBlockBody in testlib
- Add NFData and EncCBOR deriving for DijkstraBlockBody newtype
- Export DijkstraBlockBodyRaw and MkDijkstraBlockBody from Internal module
- Add custom CBOR generator for block_body
- Use deriving via Mem for Annotator BlockBody decoder
- Reimplement alignedValidFlags using IntSet
- Update changelogs

Verify that the decoder rejects big integers (CBOR tags 2/3) outside
the valid CBOR int range of -2^64 .. 2^64-1, and accepts values at
the boundaries. Also fix an off-by-one in the comment documenting
the supported range.

Co-authored-by: teodanciu <[email protected]>
Co-authored-by: Alexey Kuleshevich <[email protected]>

Add queryStakeDelegDeposits (GetStakeDelegDeposits) query leveraging
EraAccounts. The use of Map.restrictKeys wasn't possible earlier with
UMap which only allowed for single-credential lookups.