commands: add `rbfpsbt` command #1545

Job	Run time
linter	35s
linter_gui	5m 25s
unit_tests (1.54, ubuntu-latest)	5m 6s
unit_tests (1.54, macOS-latest)	7m 35s
unit_tests (1.54, windows-latest)	7m 0s
unit_tests (nightly, ubuntu-latest)	56s
unit_tests (nightly, macOS-latest)	1m 39s
unit_tests (nightly, windows-latest)	1m 30s
unit_tests_gui (1.65, ubuntu-latest)	7m 1s
unit_tests_gui (1.65, macOS-latest)	11m 58s
unit_tests_gui (1.65, windows-latest)	9m 1s
unit_tests_gui (nightly, ubuntu-latest)	2m 40s
unit_tests_gui (nightly, macOS-latest)	3m 4s
unit_tests_gui (nightly, windows-latest)	3m 54s
	1h 7m 24s

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