Add demo DUT. #6981

Job	Run time
license-check	9s
Basic linting	1m 4s
bittide-instances synthesis matrix generation	23s
bittide-instances hardware-in-the-loop test matrix generation	24s
Build dependencies	2m 41s
Rust Lints	32s
bittide-experiments unittests	46s
Bittide tests	5m 43s
Firmware Support Unit Tests	2m 19s
bittide-instances doctests	54s
bittide-instances unittests	58s
synth (demoTest, test)	12m 12s
Firmware Limit Checks	45s
HITL (demoTest, test)	1m 55s
Generate clock control report	0s
All jobs finished	2s
	30m 47s

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