(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.
```

+ HelpExampleCli("gettransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\" true")
            + HelpExampleRpc("gettransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\"")
        );
    LOCK2(cs_main, pwalletMain->cs_wallet);
    uint256 hash;
    hash.SetHex(params[0].get_str());
    isminefilter filter = ISMINE_SPENDABLE;
    if(params.size() > 1)
        if(params[1].get_bool())
            filter = filter | ISMINE_WATCH_ONLY;
    UniValue entry(UniValue::VOBJ);
    if (!pwalletMain->mapWallet.count(hash))
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid or non-wallet transaction id");
    const CWalletTx& wtx = pwalletMain->mapWallet[hash];
    CAmount nCredit = wtx.GetCredit(filter);
    CAmount nDebit = wtx.GetDebit(filter);
    CAmount nNet = nCredit - nDebit;
    CAmount nFee = (wtx.IsFromMe(filter) ? wtx.GetValueOut() - nDebit : 0);
    entry.push_back(Pair("amount", ValueFromAmount(nNet - nFee)));
    if (wtx.IsFromMe(filter))
        entry.push_back(Pair("fee", ValueFromAmount(nFee)));
    WalletTxToJSON(wtx, entry);
    UniValue details(UniValue::VARR);
    ListTransactions(wtx, "*", 0, false, details, filter);
    entry.push_back(Pair("details", details));
    string strHex = EncodeHexTx(static_cast<CTransaction>(wtx));
    entry.push_back(Pair("hex", strHex));
    return entry;
}
UniValue abandontransaction(const UniValue& params, bool fHelp)