Adding support of multiple appSrc(s) in ModuleScopePlugin

Created by: froyog

I'm currently working on a project which invovled two src folder (/src and /docs/src). And when I try to import files from /docs/src ModuleScopePlugin prevents me from doing it since /docs/src falls outside of /src. So I'm wondering if ModuleScopePlugin can also accepts an array as its first parameter so that I can solve this problem with new ModuleScopePlugin([paths.appSrc, paths.docsSrc], [paths.appPackageJson]) (docsSrc is already defined in paths.js)