(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.
```

{
    CWalletDB walletdb(pwalletMain->strWalletFile);
    CAccount account;
    walletdb.ReadAccount(strAccount, account);
    if (!bForceNew) {
        if (!account.vchPubKey.IsValid())
            bForceNew = true;
        else {
            
            CScript scriptPubKey = GetScriptForDestination(account.vchPubKey.GetID());
            for (map<uint256, CWalletTx>::iterator it = pwalletMain->mapWallet.begin();
                 it != pwalletMain->mapWallet.end() && account.vchPubKey.IsValid();
                 ++it)
                BOOST_FOREACH(const CTxOut& txout, (*it).second.vout)
                    if (txout.scriptPubKey == scriptPubKey) {
                        bForceNew = true;
                        break;
                    }
        }
    }
    
    if (bForceNew) {
        if (!pwalletMain->GetKeyFromPool(account.vchPubKey))
            throw JSONRPCError(RPC_WALLET_KEYPOOL_RAN_OUT, "Error: Keypool ran out, please call keypoolrefill first");
        pwalletMain->SetAddressBook(account.vchPubKey.GetID(), strAccount, "receive");
        walletdb.WriteAccount(strAccount, account);
    }
    return CBitcoinAddress(account.vchPubKey.GetID());
}
UniValue getaccountaddress(const UniValue& params, bool fHelp)