Include delegations in runtime account endpoint

[buberdds]

RuntimeAccountsAddressDelegations* endpoints were added lately to Nexus.
Can we update runtime acc endpoints with additional props?

https://nexus.oasis.io/v1/spec/v1.html#/paths/~1%7Bruntime%7D~1accounts~1%7Baddress%7D/get

[
    {
        "balance": "95879755420000000000",
        "token_decimals": 18,
        "token_symbol": "ROSE"
    }
]

vs
https://nexus.oasis.io/v1/spec/v1.html#/paths/~1consensus~1accounts~1%7Baddress%7D/get

available: "18914199532"
debonding: "0"
debonding_delegations_balance: "100329883729"
delegations_balance: "602178920842"

sample mockup

[lukaw3d]

Would unblock oasisprotocol/explorer#1800