Genesis config file parsing

[scarmuega]

We want to be able to load genesis config files (byron, shelley, alonzo, etc) as defined by the Haskell node implementation in order to use those values in downstream components.

DoD:

• we can load & parse Byron genesis json files into structs
• we can load & parse Shelley genesis json files into structs
• we can load & parse Alonzo genesis json files into structs
• we can load & parse Conway? genesis json files into structs

[rvcas]

Did I see this being started somewhere already? Or am I confused?

[scarmuega]

Did I see this being started somewhere already? Or am I confused?

We had #59 but I ended up constraining the scope to just Byron genesis because I needed a way to generate those initial UTxOs. Added this issue to keep track of work for the remaining config files.