Encore: configure runtime environment if not already configured

[Kocal]

Q	A
License	MIT

With this, we directly fix the error:

Encore.setOutputPath() cannot be called yet because the runtime environment
doesn't appear to be configured. Make sure you're using the encore executable
or call Encore.configureRuntimeEnvironment() first if you're purposely not
calling Encore directly.

when using Encore/Webpack without the encore command (npm run encore ...).

This is useful when:

• using tools that depends of webpack.config.js, like ESLint with the import plugin, Karma, ...
• using an IDE with Webpack integration

This doesn't break anything if you use encore command, since it already configure the runtime environment.

See:

• https://symfony.com/doc/current/frontend/encore/faq.html#how-do-i-integrate-my-encore-configuration-with-my-ide
• Add a public method to know whether the runtime is configured webpack-encore#500
• Add Encore.configureRuntimeEnvironment() method to the public API webpack-encore#115

What do you think about it?
Thanks :)

[ghost]

Pull request passes validation.

[ghost]

Pull request passes validation.