Do not install required pip packages on behalf of users

[ptheywood]

Emit a CMake Fatal Error during configuraition for missing required python packages, rather than installing them into the users environment.

Wheel, setuptools and optionall venv are requred.

Installing into --user automatically would fail in some cases, and installing not into user into a not-generated venv is bad form.

Closes #639

Also switches from the deprectaed setup.py install to use build --wheel.
Closes #947.

[ptheywood]

Using a fresh venv on my ubuntu system, which doesn't contain wheel (but does contain setuptools and venv):

cmake .. -DBUILD_SWIG_PYTHON=ON

...

-- -----Configuring Project: pyflamegpu-----
-- pyflamegpu-2.0.0a3 (2.0.0a3+cuda118)
-- Found python module: setuptools (version "59.6.0")
CMake Error at swig/python/CMakeLists.txt:221 (message):
    Unable to find required python module "wheel".
    Please install this to your python environment, e.g.
      python3 -m pip install wheel
Call Stack (most recent call first):
  swig/python/CMakeLists.txt:231 (search_python_module)


-- Configuring incomplete, errors occurred!

After installing via python3 -m pip install wheel, it configures successfully.

[Robadob]

Looks sensible.

Would we benefit from a requirements.txt or similar?

[ptheywood]

Would we benefit from a requirements.txt or similar?

We could, but things like venv are optional (and not always installable via pip). It would only contain wheel and setuptools, and I'd be reluctant to pin versions given the broad range of python version support (and subsequent dependabot spam).

Individual examples might then have additional dependencies, including pflamegpu but that is not installable via name via pip anyway, so would just cause use of requirements.txt to fail if included.

I'm inclined to leave it for the future (though it might not hurt to open an issue?)

[mondus]

Can you add a brief sentence in README.md about where cmake will search for python and that cmake can be run from inside a virtual environment with the dependencies installed. Seems like this PR would be a good place for this to go in as its adding python discrepancies.