[cmake] Honor CMAKE_BUILD_PARALLEL_LEVEL when building PETSc or LIS.

1. Feature description was added to the changelog
2. Tests covering your feature were added?
3. Any new feature or behavior change was documented?

changed milestone to %6.5.0

added workflowin development label

requested review from @TobiasMeisel

added workflowplease review label and removed workflowin development label

approved this merge request

• tested on juwels 2023/03/19
• compiled, but (still) very slow CPM in TFEL, VTK and (optionally) PETSc
• no unexpected spawned processes found (sporadic checking with htop)

approved this merge request

removed workflowplease review label

mentioned in commit e87f1b07

merged