Add function to load a contract from directory/file

[nielstron]

A function that simply tries its best to load a contract and choosing the correct action based on being passed

• a Plutus blueprint
• a script.plutus json file
• a script.cbor singly wrapped cbor hex
• a script.addr script address
• a script.policy_id policy id
• a directory containing any of the above artifacts

Context

Avoids problems like https://github.com/Python-Cardano/pycardano/discussions/240

OpShin just creates a folder like the above

Same as https://github.com/OpShin/opshin/issues/123, ideally no code duplication required.