Merging branch 'corr0'  into 'main'.

See merge request !843

Merging branch 'mod1'  into 'main'.

See merge request !842

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

Also check for the existence of the main executable.

For all platforms, the Python wheel is copied into the package build directory
to be bundled with the package.

As the CMake script is to be used for multiple platforms, renamed FixAppleBundle.cmake.in => FixPack.cmake.in

The Python wheel must be produced before making the BA package, as the wheel
must be included withing the package.

Merging branch 'corrgui'  into 'main'.

See merge request !840

Merging branch 'simpl1'  into 'main'.

See merge request !839

Merging branch 'i287'  into 'main'.

See merge request !838

Merging branch 'i192'  into 'main'.

See merge request !837

Merging branch 'i184'  into 'main'.

See merge request !832