Recommend a particular folder structure, rather than putting everything in the project root

[fkohrt]

This way, we can also demonstrate how to deal with relative vs. absolute paths and recommend a project-based workflow.

Of course, this is complicated by the fact that notebooks generally assume the working directory to be in their storage location, rather than the root folder of the project.

Either do the following:

```{r}
#| cache: false
#| include: false

knitr::opts_knit$set(root.dir = rprojroot::find_rstudio_root_file())
```

Or set execute-dir within _quarto.yml:

project:
  execute-dir: project

With rmarkdown, one would do the following:

rmarkdown::render(..., knit_root_dir = rprojroot::find_rstudio_root_file())

Note: package rprojroot is prefered for non-interactive use over here.

In RStudio, one can also set Tools > Global Options > R Markdown > Evaluate chunks in directory: Project