Add handling for arrays in webpackConfig processing

[tolysz]

What did you implement:

Adds handling of arrays in webpack.config.js when packaging individually. Webpack itself handles such configs already.
Closes #XXXXX

How did you implement it:

How can we verify it:

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Make sure code coverage hasn't dropped
• Provide verification config / commands / resources
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: NO
Is it a breaking change?: NO

[j0k3r]

Can you add a test with an array config of webpack?