Refactor config.rake tasks

What does this Merge Request do and why?

This implements some refactors to have a more standardized code that is easier to understand and maintain:

• Extract inline template for support/makefiles/Makefile.config.mk and move it to an ERB file.
• Remove many of the inline defined code inside config.rake, extracting them to helper classes.
• Rewrite how we register template files using the helper class
• Rewrite how we register make tasks based on template files using the helper class
• Migrate Snowplow related logic to use the config tasks and behave as the other templates
• Relocate Snowplow templates to its own folder for consistence

Merge Request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise Issue to follow-up.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.