We use the saved previous outputs (plus maybe some new ones?) to build a
psbt for an RBF request.
RBFs utxo reuse is now working so we can unfail the test (and update
it to reflect that the lease sticks around through an RBF cycle).
Changelog-Fixed: Plugins: `funder` now honors lease requests across RBFs
Any file in this directory which is executable and whose name only
consists of alphanumeric characters, space, '.', '-' or '_' will be
automatically loaded when lightningd starts (unless suppressed with
commandline options).