commands: add `rbfpsbt` command #1549

Job	Run time
linter	35s
linter_gui	5m 29s
unit_tests (1.54, ubuntu-latest)	5m 15s
unit_tests (1.54, macOS-latest)	7m 48s
unit_tests (1.54, windows-latest)	6m 47s
unit_tests (nightly, ubuntu-latest)	54s
unit_tests (nightly, macOS-latest)	1m 49s
unit_tests (nightly, windows-latest)	2m 0s
unit_tests_gui (1.65, ubuntu-latest)	7m 9s
unit_tests_gui (1.65, macOS-latest)	13m 44s
unit_tests_gui (1.65, windows-latest)	9m 26s
unit_tests_gui (nightly, ubuntu-latest)	2m 33s
unit_tests_gui (nightly, macOS-latest)	4m 20s
unit_tests_gui (nightly, windows-latest)	4m 48s
	1h 12m 37s

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