Removes a few files from the installed package

[pieterocp]

Since as far as I am aware, these are helpful when developing, but not too helpful when installed.

(and removed a few off the guidance from https://docs.npmjs.com/cli/v11/using-npm/developers#keeping-files-out-of-your-package)

Tested with a npm pack && tar -xvzf *.tgz && rm -rf package *.tgz which should detail what files are left over (thanks to Jeff D /@jdx .

[pieterocp]

Dear contributors, can someone review this? It's pretty small update but does add up to send less traffic whenever someone does install this package.

(I spotted these when having a look at some CLI output packaging theses files. I hope this falls under Contributing Anything else constructively helpful.)