Made runTask a static method in ParallelTaskManager #3430

Job	Run time
mac / macports (macos-12)	1s
mac / macsimple (macos-12)	1s
mac / macports (macos-14)	3m 36s
linux / linux (-doc-mpi-)	44m 25s
mac / macsimple (macos-14)	5m 47s
mac / macports (+allmodules, macos-12)	1s
codecheck / codecheck	44m 29s
linux / linux (-mpi-)	52m 47s
linux / linux (-coverage-mpi-)	1h 0m 47s
linux / linux (-debug-)	43s
conda / conda (ubuntu-20.04)	11m 35s
linux / linux (-debug-mpi-)	2m 10s
conda / conda (macos-12)	1s
linux / linux (-intel-)	8m 28s
docker / docker (fedora39)	20m 16s
conda / conda (macos-14)	2m 39s
docker / docker (rocky8)	24m 6s
linux / linux (-pycv-mpi-)	19m 15s
	5h 1m 7s

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