* make tests a module
This is needed because we want to have a common.py file at the root of the Test folder and the only way to get relative imports working is to make everything a module

* skip tests with mpi
Skip all existing tests under mpi
* mark legacy tests
Skip them by default
* change github actions
* Add SR MPI tests

* fix mpi tests

* simplify sr tests

* fixup!

* fixup!

* document a bit more

* switch to myst_parser instead of recommonmark

recommonmark is now deprecated in favour of myst parser

* Add documentation for contributors

* update README badges

- change the anaconda badge to display last version - - uploaded rather than nothing
- remove travis badge, as we dont use it anymore
- add codecov badge ( i never find the right link)
- remove github issue badget (it's just above there)
[ci skip]