commands: add `rbfpsbt` command #1533

Job	Run time
linter	33s
linter_gui	5m 27s
unit_tests (1.54, ubuntu-latest)	5m 11s
unit_tests (1.54, macOS-latest)	11m 13s
unit_tests (1.54, windows-latest)	6m 24s
unit_tests (nightly, ubuntu-latest)	58s
unit_tests (nightly, macOS-latest)	1m 37s
unit_tests (nightly, windows-latest)	2m 27s
unit_tests_gui (1.65, ubuntu-latest)	6m 30s
unit_tests_gui (1.65, macOS-latest)	12m 58s
unit_tests_gui (1.65, windows-latest)	9m 27s
unit_tests_gui (nightly, ubuntu-latest)	2m 47s
unit_tests_gui (nightly, macOS-latest)	5m 11s
unit_tests_gui (nightly, windows-latest)	4m 29s
	1h 15m 12s

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