feat: enable multiprocessing on compile object level

[MatteoVoges]

Proposed Changes

• new flag --multiprocess-objects
• splits compile_obj from targets and run them in parallel, to balance out heavy targets

Performance Measurements

• for inventories with targets with equally distributed target to compile_obj ratio --> 1:1
• for inventories with unbalanced ratios: performance gain up to 400 %

Problems with tests

The tests are failing because of the removal target. The order of execution matters in this target. I think, we should change this example because compile objects should not depend on each other neither different targets should.