swaps: potential send change to lightning option improvements

[f321x]

Description

There are multiple rough edges when using the send change to lightning option, in Qt I noticed:

• The (onchain) tx fee shown for the transaction is misleading as it doesn't contain the swap fees. I think it would be nice if the tx fee field would simply show the whole expected fee, including the swap fee. So there is only a single fee value and it represents the true fee.
• No swap fee is shown at all before the swap is initiated, which could lead to paying more fees than expected.
• coin selection doesn't respect the min/max swap amounts and has no knowledge of them (as they are only fetched after constructing the tx). This results in unreliable tx flow as the tx will often fail if the coin selection happens to select utxos that are outside of the supported swap limits. If no UTXO is available in the possible swap range the user should not be able to initiate the tx, he should either be forced to disable send change to lightning or select a different swap provider if available.
• It is possible to set a very low onchain fee which could result in the swap output being refunded and other unpleasant UX, the minimal allowed ETA/tx fee should be limited (same as in the QML forward swap finalizing screen PR, see qml: let user finalize forward swap onchain tx before initiating swap #9992).