Proposal for updating the R container

Hello there, I'm interested in helping update the R container,
after spending some time working on the build errors I have written a patch,
but I want to discuss the changes before opening a PR because they are significant:

- Upgrade R to 4.4
the latest R available on Kaggle is 3 years old now, it's about time we get an update ;)

- Drop mxnet
as of 2023-09, the project has been [retired](https://attic.apache.org/projects/mxnet.html).

- Remove packages: rgdal, rgeos
these packages have been [removed from CRAN](https://cran.r-project.org/web/packages/rgdal/index.html):
`Archived on 2023-10-16 at the request of the maintainer. Consider using 'sf' or 'terra' instead.`

- Install the latest versions of the packages: randomForest, terra, ranger, imager
the version of these packages is fixed on `package_installs.R`,
the comments imply there is context for these ( internal bug tracker ?), but it's not clear why or if they are still needed.

- Use [pak](https://pak.r-lib.org/index.html) to install packages
The build is currently failling here:

```R
r$> utils:::.make_dependency_list(pkgs, allPackages, recursive = TRUE)
Error in tools:::.extract_dependency_package_names(x) :
non-character argument

r$> traceback()
4: tools:::.extract_dependency_package_names(x)
3: unique.default(tools:::.extract_dependency_package_names(x))
2: .clean_up_dependencies(info2[i, ])
1: utils:::.make_dependency_list(pkgs, allPackages, recursive = TRUE)
```

`package_installs.R` uses `utils:::.make_dependency_list`,
this is an internal function and is prone to changing its behavior without warning,
which is what I think happened here.

pak can do parallel downloads and parallel installation of packages, [among other features](https://pak.r-lib.org/reference/features.html).

I think that by using pak most of the `package_installs.R` code becomes redundant, and the script can be simplified significantly.

of course, none of these are required but it is what I think would be better, let me know what you think.