COIN-OR — prompts

Make the Raku package "COIN-OR" using Raku's "NativeCall" (interfacing the optimization library COIN-OR)
and libraries installed with the shell scripts in "./README.md".
Please, make the small-model example in "./examples" and make corresponding tests in "./xt".

Make the corresponding changes to make that package also work on macOS:
- Add env variables for the variables locations the Raku package can use
- Provide corresponding instructionsions in REAME.md

Work out the LP example of Google OR-Tools with Raku's "COIN-OR":
https://developers.google.com/optimization/lp/lp_example

Put the code in the file "./examples/solving-a-linear-programming-problem.raku".

Work out the Stingler Diet example of Google OR-Tools with Raku's "COIN-OR":
https://developers.google.com/optimization/lp/stigler_diet

Put the code in the file "./examples/solving-stingler-diet.raku".

Work out the Assignment example of Google OR-Tools with Raku's "COIN-OR":
https://developers.google.com/optimization/assignment/assignment_example

Put the code in the file "./examples/assigment-problem.raku".

I want to be able to specify which linear programming method use -- Simplex or Interior Point.
Change the package code accordingly.
Change an example script "./examples/solving-stingler-diet.raku" to shows the use of method.

For each method of the class COIN-OR::Model add usage message (or WHY) for each argument. E.g. Str:D $name, #= variable name.

Above each method of the class COIN-OR::Model add usage message with the `#|` notation. For example:
```raku
#| Add constraint
method add(...
```

Make an installation script in "./resources" that installs the COIN-OR libraries and the Raku package for both Linux or macOS. 
Make a separate script for Windows.