txscript/v4/stdscript migration

[chappjc]

This migrates to the new txscript/v4/stdscript package.

New script class types in dbtypes and api/types are created to maintain the same script class strings.

This uncovered a pg DB bug that has existed since the birth of the dcrpg package. Tickets have always had the is_multisig BOOL column set to false. A DB upgrade would be needed to identify p2sh tickets, or just remove the is_multisig column entirely. I think the idea of this column was to distinguish solo (P2PKH) and legacy stakepool (P2SH) tickets. For some reason the code was checking the subtype of the stake submission but only setting is_multisig was multisig, which was never the case since it is either pkh or sh. I've confirmed that there are no instances of is_multisig being true in a mainnet tickets table. I think I will remove this since clearly no one looks at the column, and the corresponding output type can be determined via the vouts table.

[chappjc]

Script classes are now being kept unchanged despite the more fine-grained stdscript types on account of the new api and db types in the following key places:

1. Display on explorer pages
2. Encoded in JSON API endpoints
3. Stored in the postgresql DB

In addition to keeping the different stake subtypes combined (e.g. sstxchange-scripthash || sstxchange-pubkeyhash == sstxchange), both (1) and (2) also translate the special odd numbered nulldata outputs of tickets/stakesubmissions as sstxcommitment. The database has always stored these as nulldata, and that is unchanged.

Running as expected on https://tip.dcrdata.org with dcrd 1.7/master.

[chappjc]

3 days on tip.dcrdata.org. script_type summary in postgres:

# select script_type, count(*) from vouts group by script_type;
   script_type   |  count   
-----------------+----------
 nonstandard     |        1
 nulldata        | 11039755
 pubkey          |      951
 pubkeyalt       |        1
 pubkeyhash      | 24744771
 scripthash      |   684404
 sstxchange      |  4278104
 stakegen        |  4150118
 stakerevoke     |    83265
 stakesubmission |  3123067
 treasuryadd     |    63718
 treasurygen     |        1
(12 rows)

This indicates the stored script types are stable with dbtypes.ScriptClass translating from the stdscript type to the internal DB type.

The explorer pages are also showing the same script types, including the "sstxcommitment" pseudo-type, along with the script version: https://tip.dcrdata.org/tx/78f070e11fbccdfc2bb13e0f7b221c873d1656997ac47b91b90c3617d367170c

API:

   "vout": [
    {
      "value": 196.73779166,
      "n": 0,
      "version": 0,
      "scriptPubKey": {
        "asm": "OP_SSTX OP_DUP OP_HASH160 064f47471cf7378c93b2330c9ac954cf69692b5d OP_EQUALVERIFY OP_CHECKSIG",
        "hex": "ba76a914064f47471cf7378c93b2330c9ac954cf69692b5d88ac",
        "version": 0,
        "reqSigs": 1,
        "type": "stakesubmission",
        "addresses": [
          "DsRYGWwfSz3pnGgWmSzAzLMVb9NrZWDVa19"
        ]
      }
    },
    {
      "value": 0,
      "n": 1,
      "version": 0,
      "scriptPubKey": {
        "asm": "OP_RETURN 2a372905e48a34601d842ff88bbed0d117932afa8217a694040000000058",
        "hex": "6a1e2a372905e48a34601d842ff88bbed0d117932afa8217a694040000000058",
        "version": 0,
        "type": "sstxcommitment",
        "addresses": [
          "DsUp7x65r9eBnrzoeF6Y6ncZvuaLfXWdoSh"
        ],
        "commitamt": 196.73782146
      }
    },
    {
      "value": 0,
      "n": 2,
      "version": 0,
      "scriptPubKey": {
        "asm": "OP_SSTXCHANGE OP_DUP OP_HASH160 0000000000000000000000000000000000000000 OP_EQUALVERIFY OP_CHECKSIG",
        "hex": "bd76a914000000000000000000000000000000000000000088ac",
        "version": 0,
        "reqSigs": 1,
        "type": "sstxchange",
        "addresses": [
          "DsQxuVRvS4eaJ42dhQEsCXauMWjvopWgrVg"
        ]
      }
    }
  ]