Velocity BCs in all coordinate directions, new example cases, nonpolytropic bc refactor #945

Job	Run time
Georgia Tech \| Phoenix (NVHPC) (cpu)	2h 17m 38s
Georgia Tech \| Phoenix (NVHPC) (gpu)	1h 32m 11s
Github (ubuntu, mpi, debug, true)	30m 43s
Github \| Docker	53m 23s
Github (ubuntu, mpi, debug, false)	1h 5m 46s
Github (ubuntu, mpi, no-debug, true)	58m 21s
Github (ubuntu, mpi, no-debug, false)	53m 41s
Github (ubuntu, no-mpi, debug, true)	26m 24s
Github (ubuntu, no-mpi, debug, false)	15m 7s
Github (ubuntu, no-mpi, no-debug, true)	31m 48s
Github (ubuntu, no-mpi, no-debug, false)	17m 39s
Github (macos, mpi, debug, false)	44m 50s
Github (macos, mpi, no-debug, false)	46m 47s
Github (macos, no-mpi, debug, false)	14m 41s
Github (macos, no-mpi, no-debug, false)	33m 49s
	12h 2m 48s

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