Remove hardcoded `withmpi` setting when AiiDA 2.5 is realeased

[yakutovicha]

There was a bug introduced in AiiDA core 2.3. This required us to set Calcinfo.withmpi=True for several plugins.

The bug in AiiDA core was fixed recently in aiidateam/aiida-core#6218.

As soon as AiiDA 2.5 is released, we need to revert #152.