Add extra support for more getters for the Validator class

[marcin-cb]

What changed? Why?

Adding support for more getters to expose the data behind the Validator object.

Example

validator.toJSON()

{"asset_id":"eth","details":{"activationEpoch":"epoch-1","balance":{"amount":"100","asset":{"asset_id":"eth","network_id":"ethereum-holesky"}},"effective_balance":{"amount":"200","asset":{"asset_id":"eth","network_id":"ethereum-holesky"}},"exitEpoch":"exit-epoch-2","index":"0","public_key":"public-key-1","slashed":false,"withdrawableEpoch":"withdrawable-epoch-3","withdrawal_address":"withdrawal-address-1"},"network_id":"ethereum-holesky","status":"active","validator_id":"validator-1"}

Qualified Impact