Add an implementation of USYMLQR #1217

Job	Run time
setup_matrix	1m 50s
break (PartiallySeparableNLPModels, latest)	10m 49s
break (PartiallySeparableNLPModels, stable)	8m 4s
break (Percival, latest)	6m 42s
break (Percival, stable)	6m 45s
break (CaNNOLeS, latest)	6m 24s
break (CaNNOLeS, stable)	5m 57s
break (PartitionedVectors, latest)	1m 13s
break (PartitionedVectors, stable)	1m 10s
break (DCISolver, latest)	5m 32s
break (DCISolver, stable)	5m 31s
break (JSOSolvers, latest)	11m 17s
break (JSOSolvers, stable)	11m 3s
break (PartiallySeparableSolvers, latest)	3m 37s
break (PartiallySeparableSolvers, stable)	3m 37s
break (RipQP, latest)	7m 49s
break (RipQP, stable)	7m 56s
break (AdaptiveRegularization, latest)	14m 24s
break (AdaptiveRegularization, stable)	13m 36s
break (FletcherPenaltySolver, latest)	26m 1s
break (FletcherPenaltySolver, stable)	27m 18s
upload	5s
	3h 6m 40s

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