commands: add `rbfpsbt` command #1550

Job	Run time
linter_gui	5m 47s
linter	36s
unit_tests (1.54, ubuntu-latest)	5m 11s
unit_tests (1.54, macOS-latest)	7m 42s
unit_tests (1.54, windows-latest)	6m 50s
unit_tests (nightly, ubuntu-latest)	54s
unit_tests (nightly, macOS-latest)	1m 18s
unit_tests (nightly, windows-latest)	1m 58s
unit_tests_gui (1.65, ubuntu-latest)	6m 57s
unit_tests_gui (1.65, macOS-latest)	12m 22s
unit_tests_gui (1.65, windows-latest)	9m 22s
unit_tests_gui (nightly, ubuntu-latest)	2m 36s
unit_tests_gui (nightly, macOS-latest)	3m 47s
unit_tests_gui (nightly, windows-latest)	4m 6s
	1h 9m 26s

Provide feedback