Fix #236

Closes #238 and #236

See merge request !918

[cmake] Add a user-facing interface to add additional pip params

See merge request !919

fix the order in which dune modules are processed when calling `make install_python` with `setup-dunepy`.
Also add a `pyproject.toml` to make sure `wheel` is available when installing dune-common. Also added `wheel`
to python dependencies in dune.module so that downstream modules can rely on `wheel` being available.

cmake arguments were stored as a dict, having mainly definitions in mind.

This lead to several issues, as cmake has many different kinds of
commmand line arguments.

Instead of storing these arguments as a dict, we now only store them as
a list, which can directly be passed to Popen, when spawning the cmake
process.

Fixes #238.

The `dune.module` file containes meta-data and optionally bash function
definitions to hook into dunecontrol.

We now use regular expression to properly parse the meta-data.

[test][python] allow to overwrite the interpreter for python test command

See merge request !915

No support for passing multiple interpreters intended.

When using dune_python_add_test the SCRIPT is executed by default with
the detected python interpreter. The optional INTERPRETER parameter allows
to overwrite this setting, e.g. to pass additional command line arguments
or to execute the tests using pytest.

add Python3_EXECUTABLE to `dune_python_add_test`

See merge request !914

a python script to 'dune_python_add_test'

downstream modules:
change `COMMAND ${PYTHON_EXECUTABLE} test.py` by `COMMAND test.py`

Deprecate DUNE_DEPRECATE and _MSG

Closes #91

See merge request !777

Use on C++14's [[deprecated]] instead.

Feature/find python3

See merge request !806