Do not hold Python's GIL when running commands #54

Job	Run time
docker / docker (fedora39)	21m 4s
linux / linux (-doc-mpi-)	39m 12s
conda / conda (ubuntu-20.04)	11m 28s
docker / docker (rocky8)	23m 16s
codecheck / codecheck	44m 15s
linux / linux (-mpi-)	52m 18s
conda / conda (macos-13)	14m 57s
linux / linux (-coverage-mpi-)	1h 1m 8s
conda / conda (macos-14)	5m 22s
mac / macports (macos-13)	24m 16s
linux / linux (-debug-)	31m 3s
mac / macsimple (macos-13)	14m 12s
mac / macports (macos-14)	5m 8s
linux / linux (-debug-mpi-)	41m 42s
mac / macsimple (macos-14)	4m 22s
mac / macports (+allmodules, macos-13)	39m 53s
linux / linux (-intel-)	48m 8s
linux / linux (-pycv-mpi-)	19m 5s
linux / linux (-nvhpc-mpi-)	54m 25s
	9h 15m 14s

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