(from discussion on IRC. Currently a global `settxfee` has to be changed to override the fee rate, it would make sense to be able to specify it on a per-transaction basis. This would continue #7518)

```
-*- jonasschnelli thinks we should probably add a optional feerate parameter to fundrawtransaction
<wumpus> jonasschnelli: there isn't one yet?
-*- jonasschnelli looking..
<wumpus> I'm surprised, would be so much better than changing a global
<jonasschnelli> no.. i don't think so. Maybe there is a PR.
<sipa> there is a pr
<jonasschnelli> Hard to keep track of everything. :)
<wumpus> no, the PR does it wrong
```

Regarding implementation:

```
<jonasschnelli> The ugly thing is, that CreateTransaction uses the static DEFAULT_TARGET
<wumpus> passing in an optional feerate would be the obvious thing to do
<jonasschnelli> So, this would require some refactoring.
<sipa> just add a confirmation target to coincontrol
<jonasschnelli> Yes. This sounds good.
<wumpus> right, just slap it into coincontrol
<sipa> wasn't there a PR that added a bunch of options to fundrawtransaction?
<sipa> including that
<jonasschnelli> Not the feerate.
<jonasschnelli> But the rest is merged.
```

"    \"blockindex\": n,          (numeric) The index of the transaction in the block that includes it. Available for 'send' and 'receive' category of transactions.\n"
            "    \"blocktime\": xxx,         (numeric) The block time in seconds since epoch (1 Jan 1970 GMT).\n"
            "    \"txid\": \"transactionid\",  (string) The transaction id. Available for 'send' and 'receive' category of transactions.\n"
            "    \"time\": xxx,              (numeric) The transaction time in seconds since epoch (Jan 1 1970 GMT).\n"
            "    \"timereceived\": xxx,      (numeric) The time received in seconds since epoch (Jan 1 1970 GMT). Available for 'send' and 'receive' category of transactions.\n"
            "    \"comment\": \"...\",       (string) If a comment is associated with the transaction.\n"
            "    \"label\" : \"label\"       (string) A comment for the address/transaction, if any\n"
            "    \"to\": \"...\",            (string) If a comment to is associated with the transaction.\n"
             "  ],\n"
            "  \"lastblock\": \"lastblockhash\"     (string) The hash of the last block\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("listsinceblock", "")
            + HelpExampleCli("listsinceblock", "\"000000000000000bacf66f7497b7dc45ef753ee9a7d38571037cdb1a57f663ad\" 6")
            + HelpExampleRpc("listsinceblock", "\"000000000000000bacf66f7497b7dc45ef753ee9a7d38571037cdb1a57f663ad\", 6")
        );
    LOCK2(cs_main, pwalletMain->cs_wallet);
    CBlockIndex *pindex = NULL;
    int target_confirms = 1;
    isminefilter filter = ISMINE_SPENDABLE;
    if (params.size() > 0)
    {
        uint256 blockId;
        blockId.SetHex(params[0].get_str());
        BlockMap::iterator it = mapBlockIndex.find(blockId);
        if (it != mapBlockIndex.end())
            pindex = it->second;
    }
    if (params.size() > 1)
    {