(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.
```

int nConf = std::numeric_limits<int>::max();
        bool fIsWatchonly = false;
        if (it != mapTally.end())
        {
            nAmount = (*it).second.nAmount;
            nConf = (*it).second.nConf;
            fIsWatchonly = (*it).second.fIsWatchonly;
        }
        if (fByAccounts)
        {
            tallyitem& item = mapAccountTally[strAccount];
            item.nAmount += nAmount;
            item.nConf = min(item.nConf, nConf);
            item.fIsWatchonly = fIsWatchonly;
        }
        else
        {
            UniValue obj(UniValue::VOBJ);
            if(fIsWatchonly)
                obj.push_back(Pair("involvesWatchonly", true));
            obj.push_back(Pair("address",       address.ToString()));
            obj.push_back(Pair("account",       strAccount));
            obj.push_back(Pair("amount",        ValueFromAmount(nAmount)));
            obj.push_back(Pair("confirmations", (nConf == std::numeric_limits<int>::max() ? 0 : nConf)));
            if (!fByAccounts)
                obj.push_back(Pair("label", strAccount));
            UniValue transactions(UniValue::VARR);
            if (it != mapTally.end())
            {
                BOOST_FOREACH(const uint256& item, (*it).second.txids)