Add generator options to skip reflex and stimulus

[nachiket87]

Feature

Description

As requested by @julianrubisch in #541. A user might not require a stimulus controller or an application_reflex or both to be created or modified when using the generator. This PR adds four options --skip-stimulus, --skip-reflex, --skip-app-controller and --skip-app-reflex that helps the developer customize the files required.

Fixes #541

Why should this be added

Everyone doesn't need the stimulus controller to be automatically created when using the generator. The added options can potentially save time by adding a simple flag to the generator instead of having to delete files or manually modify unwanted changes made by the generator.

Checklist

• My code follows the style guidelines of this project
• Checks (StandardRB & Prettier-Standard) are passing
• This is not a documentation update

Thank for your the opportunity to contribute again! ❤️

[julianrubisch]

LGTM and many thanks!

The only question arising is if we should shorten "application" to "app" for less typing?

[nachiket87]

@julianrubisch I agree! and done!