[addWheelToPackage] Add Python Wheel to the Package

Merging branch 'addWheelToPackage'  into 'main'.


The Python wheel is produced before the BornAgain package and added to the package on MacOS and MS-Windows platforms.
The package folder structure is the following (e.g., for Python 3.9):
```
<Package-Root>
 |
 ...
 |
 +- python
    |
    +- 3.9
       |
       +- wheel {includes the wheel file}
       |
       +- dist-packages {BA's previous Python distribution}
          |
          +- bornagain
```

The wheel can be installed via the standard Python's `pip`; e.g.,
```
python3 -m pip install BornAgain.whl
```
For further options, consult [pip's documentation](https://pip.pypa.io/en/stable).

BornAgain's previous Python distribution mechanism remains unaltered, regardless of whether it works or not.

NOTE: The mechanism to produce a complete self-contained Linux package will be added in another branch.

See merge request !841