GenesisBuilder: require module fields in genesis config json

[tgntr]

#241

e.g. if the genesis json doesn't include "aura": {"authorities": []} it should be considered as invalid genesis, but right now it is not. Go JSON tags don't provide required tags, therefore we need to find another solution.

• A possible solution may be using validate tags, e.g. validate:"required", which then can be verified with https://pkg.go.dev/github.com/go-playground/validator/v10#section-readme - needs to be tested for tinygo compatibility
• Research other possible solutions