Make `yarn install --ignore-scripts` more specific

Do you want to request a feature or report a bug? I would like to request a feature.

What is the current behavior? yarn install --ignore-scripts ignores all scripts, including the postinstall script of your project and those of your project's dependencies.

What is the desired behavior? yarn install --ignore-scripts has options to ignore either your local postinstall script (my use case), or your dependencies' postinstall scripts (mentioned in #5450). This might work best if you can specify exactly what scripts to ignore, with something like a --ignore-scripts=local,node-sass option to ignore specific scripts.

Please mention your node.js, yarn and operating system version. Node 10.16.0, Yarn 1.16.0, Mac OSX Mojave

Also, I am totally willing to work on this myself, so I would love it if someone from the Yarn team could let me know if this is something that would be accepted.