Make protocol parameters & ledger globals available through the client API

[KtorZ]

Why & What

Construction transaction to submit through a head requires client to be aware of a certain number of parameters. Those parameters are currently provided to the head as configuration files on start-up. While clients can in principle digest those same files to derive the required information, it is usually much more convenient for them to pull those pieces of information directly from the API and not worry about carrying around and maintaining configuration files. A client can then be fully autonomous by leveraging the Hydra node API.

[v0d1ch]

This has been addressed in version 0.12