commands: add `rbfpsbt` command #1546

Job	Run time
linter	36s
linter_gui	5m 28s
unit_tests (1.54, ubuntu-latest)	5m 12s
unit_tests (1.54, macOS-latest)	8m 47s
unit_tests (1.54, windows-latest)	6m 45s
unit_tests (nightly, ubuntu-latest)	52s
unit_tests (nightly, macOS-latest)	2m 18s
unit_tests (nightly, windows-latest)	1m 38s
unit_tests_gui (1.65, ubuntu-latest)	6m 46s
unit_tests_gui (1.65, macOS-latest)	11m 21s
unit_tests_gui (1.65, windows-latest)	9m 17s
unit_tests_gui (nightly, ubuntu-latest)	2m 33s
unit_tests_gui (nightly, macOS-latest)	3m 44s
unit_tests_gui (nightly, windows-latest)	5m 8s
	1h 10m 25s

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