Add support for yarn Berry

[ia3andy]

Fixes #521
Fixes #506
Fixes #474

@melloware could you give this a try?

Also it should work with yarn berry on the local machine, but the tests are made for yarn 1 installed. I am not sure how we could solve this cleanly since we tests both auto-install and manual.

For auto-install we currently follow MFP until they provide better (eirslett/frontend-maven-plugin#1012 (comment)):
"If your project is using Yarn Berry (2.x or above), the Yarn version is handled per project but a Yarn 1.x install is still needed as a "bootstrap". The plugin will try to detect .yarnrc.yml file in the current Maven project/module folder, at the root of the multi-module project if relevant, and in the folder from which the mvn command was run. If detected, the plugin will assume your project is using Yarn Berry. It will install the 1.x Yarn version you specify with yarnVersion as bootstrap, then hand over to your project-specific version."

[melloware]

I just did a fresh checkout and confirmed all tests pass with mvn clean install !!!!