Add regtest without any dependency, using pre-generated model #27

Job	Run time
codecheck / codecheck	45m 56s
docker / docker (fedora39)	21m 4s
conda / conda (ubuntu-20.04)	11m 11s
conda / conda (macos-12)	35m 29s
linux / linux (-doc-mpi-)	38m 24s
linux / linux (-mpi-)	48m 37s
docker / docker (rocky8)	23m 27s
conda / conda (macos-14)	8m 3s
mac / macports (macos-12)	17m 49s
linux / linux (-coverage-mpi-)	59m 24s
mac / macports (macos-14)	8m 40s
linux / linux (-debug-)	30m 29s
mac / macports (+allmodules, macos-12)	18m 23s
mac / macsimple (macos-12)	10m 29s
linux / linux (-debug-mpi-)	38m 22s
linux / linux (-intel-)	52m 51s
mac / macsimple (macos-14)	5m 12s
linux / linux (-pycv-mpi-)	17m 15s
	8h 11m 5s

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