[R] Make all examples standalone

There are inconsistences between whether recipes are standalone or depend on other ones. All recipes should be updated to be standalone.

e.g. https://arrow.apache.org/cookbook/r/reading-and-writing-data.html#solution-1 is not whereas the dplyr recipes are

Start with the reading-and-writing-data Solution 1 linked in the issue and compare it with the dplyr recipes to identify dependencies between recipes. Review the R cookbook examples systematically; done means every recipe is standalone rather than relying on another recipe.

Written by the indexing model from the issue text.