fix: added informative root directory install error

[Sebastian-Webster]

What & Why

I've seen many instances of people getting this error Tracker "idealTree" already exists which is caused by installing packages in a root directory. Examples of where I've seen it:
Stack Overflow
docker/for-linux#1207
Reddit
lopau.com

In those examples, they all come from missing WORKDIR in the Dockerfile, but this error could also be caused by creating a new project in the root directory of an external drive in Windows.

Changes Made

With this PR, an error has been added when trying to run npm install or npm ci inside of a root directory. It will tell the person that they are running the command in a root directory and that root directory installs are not allowed. It also tells the person to create a new folder and install the packages in there to fix the issue.

[wraithgar]

This is a breaking change if we throw here. There are some instances where this will work, and those instances will no longer work if we accept this PR.

We either need to add this to the npm 11 roadmap, or change this to an error logging output, perhaps both.

[Sebastian-Webster]

I was thinking of logging an error instead of throwing but I ended up going with throw to remove the operation not permitted error for Windows and the Tracker "idealTree" already exists error for macOS & Linux which may confuse some people.
The run on the top is with the throw and the one on the bottom is with the error log
Windows:

macOS:

We either need to add this to the npm 11 roadmap, or change this to an error logging output, perhaps both.

What would be the best route to take?