LH/dev/RexampleUpdates

[LieslH]

1. Converted all basic, intermediate and advanced R examples to Quarto interfaces (NVD example isn't working...pending a fix).
2. Changed the existing R files for the examples in (1)
   • Made things a bit more consistent across examples.
   • Removed the details/comments to make them just files with the lines needed to run the example (so all the detail and explanations is in the Quarto files instead).
   • Corrected some spelling and formatting (in some non-R files too).
3. Made a correction to the NS3 make_cost_model_distance function (unitDimensionCost to unitDimensionCosts).
4. Added the catalogue with links to examples to the readme.
   • The links for the R examples that have been converted point to the .qmd files. All others point to the original example files.
5. Added the "The examples are all hypothetical and are in no way connected to any company/location used in the datasets or to the distribution of beer in Ireland" note to the readme.
6. Updated the R readme.