Add option to exit early if imports cannot be resolved
Provide a way to exit process and throw an error when an import is unable to be resolved. If you are importing from a library Rollup will generally proceed and assume the import is an external library and it will guess the name of that library.
Description
add a cli argument or config option to ensure fenix exits and throws an error when rollup is unable to resolve a library that is not included in the external array.
Why is this change important
In a CI enviroment its important that a build fails when its unable to import a node library.
Possible Implementation
We already listen for warnings, we could create a conditonal to check for a warning code and proceed to exit the program.