feat: register build options

[webbertakken]

Changes

• This correctly registeres the options for the build command and exposes a flaw in the multi-engine logic (we don't have a way to differentiate between engines and have different cli options for each engine, depending on the project, because middleware cannot add options (not sure if yargs has a good reason for that, will need to investigate))

Checklist

• Read the contribution guide and accept the code of conduct
• Readme (updated or not needed)
• Tests (added, updated or not needed)