rename the scheduling queue

Link: https://github.com/GeneAssembly/biosal/issues/419
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
add scheduling queue with 4 levels of priority: max, high, normal, low.

Link: https://github.com/GeneAssembly/biosal/issues/419
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>