staticaddr: persist withdrawal info

[hieblmi]

addresses #936

sample output:

loop --network=regtest s listwithdrawals  
{
    "withdrawals": [
        {
            "tx_id": "9379f48176ad724396322018b1a6f04ae6a19e868bd5fb0ef1d44a28889bf6a9",
            "outpoints": [
                "4cf5f636a598ffdb4fcd9ba9f2574a4a4cb2347decce88f25c4b0efa9e7a4e58:0",
                "29062f15a18cd1fc16a7701acbd608c232e3063302716a138f34b908de371d69:1"
            ],
            "total_deposit_amount_satoshis": "500000",
            "withdrawn_amount_satoshis": "483150",
            "change_amount_satoshis": "0",
            "confirmation_height": 129
        },
        {
            "tx_id": "5f2943ef018617cc3b0e3967b6e34a1ca472c5896282425f96c2bae159da25d9",
            "outpoints": [
                "25a16919cc297f21e6d25812dd4cb6d9c5f6b7158dba25522d3b658fefd8bc0a:1",
                "be4f24f4dde6cc51b5f9e06132cf5fcad895afcb0b7b471c627cd3bd71003e53:0",
                "5a5b8c7ea10409c81c6f8637402b83c008a4f3fdf4f5b02b52069b72df50ba11:0",
                "0dc433eef2191ecefdf950e111850f650905d9b9f2350a90766fee137e476858:0",
                "5bed66d98a76bda5fa1e35cd86060e8c15a3d7432a2d3c4708294decc54852d2:0"
            ],
            "total_deposit_amount_satoshis": "1034600",
            "withdrawn_amount_satoshis": "1000000",
            "change_amount_satoshis": "34216",
            "confirmation_height": 150
        }
    ]
}

[hieblmi]

Rebased.