(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.
```

"\nAdd inputs to a transaction until it has enough in value to meet its out value.\n"
                            "This will not modify existing inputs, and will add one change output to the outputs.\n"
                            "Note that inputs which were signed may need to be resigned after completion since in/outputs have been added.\n"
                            "The inputs added will not be signed, use signrawtransaction for that.\n"
                            "Note that all existing inputs must have their previous output transaction be in the wallet.\n"
                            "Note that all inputs selected must be of standard form and P2SH scripts must be\n"
                            "in the wallet using importaddress or addmultisigaddress (to calculate fees).\n"
                            "You can see whether this is the case by checking the \"solvable\" field in the listunspent output.\n"
                            "Only pay-to-pubkey, multisig, and P2SH versions thereof are currently supported for watch-only\n"
                            "\nArguments:\n"
                            "1. \"hexstring\"           (string, required) The hex string of the raw transaction\n"
                            "2. options               (object, optional)\n"
                            "   {\n"
                            "     \"changeAddress\"     (string, optional, default pool address) The bitcoin address to receive the change\n"
                            "     \"changePosition\"    (numeric, optional, default random) The index of the change output\n"
                            "     \"includeWatching\"   (boolean, optional, default false) Also select inputs which are watch only\n"
                            "     \"lockUnspents\"      (boolean, optional, default false) Lock selected unspent outputs\n"
                            "     \"feeRate\"           (numeric, optional, default 0=estimate) Set a specific feerate (fee per KB)\n"
                            "   }\n"
                            "                         for backward compatibility: passing in a true instead of an object will result in {\"includeWatching\":true}\n"
                            "\nResult:\n"
                            "{\n"
                            "  \"hex\":       \"value\", (string)  The resulting raw transaction (hex-encoded string)\n"
                            "  \"fee\":       n,         (numeric) Fee the resulting transaction pays\n"
                            "  \"changepos\": n          (numeric) The position of the added change output, or -1\n"
                            "}\n"
                            "\"hex\"             \n"
                            "\nExamples:\n"
                            "\nCreate a transaction with no inputs\n"
                            + HelpExampleCli("createrawtransaction", "\"[]\" \"{\\\"myaddress\\\":0.01}\"") +