(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.
```

wtx.fFromMe = wtxIn.fFromMe;
                fUpdated = true;
            }
        }
        
        LogPrintf("AddToWallet %s  %s%s\n", wtxIn.GetHash().ToString(), (fInsertedNew ? "new" : ""), (fUpdated ? "update" : ""));
        
        if (fInsertedNew || fUpdated)
            if (!wtx.WriteToDisk(pwalletdb))
                return false;
        
        wtx.MarkDirty();
        
        NotifyTransactionChanged(this, hash, fInsertedNew ? CT_NEW : CT_UPDATED);
        
        std::string strCmd = GetArg("-walletnotify", "");
        if ( !strCmd.empty())
        {
            boost::replace_all(strCmd, "%s", wtxIn.GetHash().GetHex());
            boost::thread t(runCommand, strCmd); 
        }
    }
    return true;
}
/**
 * Add a transaction to the wallet, or update it.
 * pblock is optional, but should be provided if the transaction is known to be in a block.
 * If fUpdate is true, existing transactions will be updated.
 */
bool CWallet::AddToWalletIfInvolvingMe(const CTransaction& tx, const CBlock* pblock, bool fUpdate)