Support Yarn 2 package manager

[DemianX0]

Yarn 2 doesn't create a node_modules folder, instead stores packages in their original archives.
https://yarnpkg.com/features/pnp#packages-are-stored-inside-zip-archives-how-can-i-access-their-files

Related: #1211

Docs:

https://yarnpkg.com/features/pnp#compatibility-table
https://yarnpkg.com/advanced/migration

Error details:

When migrating from npm to Yarn 2 (the configuration works with npm, these packages are listed in devDependencies), after yarn install; yarn test:

>> Local Npm module "grunt-eslint" not found. Is it installed?
>> Local Npm module "grunt-karma" not found. Is it installed?
>> Local Npm module "grunt-stylelint" not found. Is it installed?
>> Local Npm module "grunt-svgmin" not found. Is it installed?