[Docs] Guides: Configuration

[jbroma]

Documentation is

• Missing
• Outdated
• Confusing
• Not sure?

Explain in Detail

needs rewrite - this should be done at the end after the final configuration changes are introduced

Your Suggestion for Changes

• how we use rspack/webpack config files
• treat webpack/rspack documentation as base for options available
• repack comes with presets in form of helper functions (they hide unnecessary complexity from you, you can always use the more verbose webpack/rspack format if you want)
• link to official templates for config files