Alpha release against dolfinx 0.6.0

Code release

This version is supposed to run on
DOLFINx version: 0.6.0 based on GIT commit: 24f86a9ce57df6978070dbee22b3eae8bb77235f of https://github.com/FEniCS/dolfinx/

We release three solvers attacking three general purpose variational problems.