Rocker scripts documentation

[eitsupi]

Currently, there is little documentation about the scripts and it is difficult to understand the purpose and use of each script.

Perhaps it would be appropriate to put README.md in the scripts directory and write the usage and purpose.
And, scripts that are not used in this repository and have not been maintained for a long time should be moved to the experimental subdirectory.

Also, to make it easier for the user to understand, the name of the scripts directory should be rocker_scripts (i.e., the same name as in the pre-built containers), I think.

[eitsupi]

It is also worth mentioning supported platforms (e.g. install_tidyverse.sh is currently not executable on arm64)

[davidbudzynski]

I second this, it's quite difficult to get your head around when there are lots of dockerfiles and many scripts which can be added on top.