Cardano Updates

In order to be able to export and import ledger data to
CIP-165 [1]. The plan is to have `scls` public library
for each era that supports it, starting with Conway.

The scls library is structured using namespaces that
CIP-165 proposes and has instances for all types.

In order to not reimplemnet too many CBOR encodings for
the types that already have instance they were implemented
via LedgerCBOR.

In order to check conformance to SCLS spec CDDL conformance
and canonicity conformance tests were introduced, so it's
possible to develop ledger types and state without looking
at scls package and rely on typechecker and tests.

[1] https://github.com/cardano-foundation/CIPs/pull/1083

Prepare an example of using scls. Example provides
abilities to:
  - read binary utxo and state files (generated by cardano-cli)
    and reencode in in scls
  - read and store the file as scls

This utility is useful as an example and for testing
scls canonicity.

Improve `writeSpec` to validate filepath.

* alonzoTransactionOutputRule
* dataRule
* datumOptionRule

* dnsNameRule
* urlRule
* voteRule
* drepCredentialRule
* committeeHotCredentialRule
* committeeColCredentialRule
* policyHashRule
* potentialLanguagesRule

Replace with updating version number update after cuddle release