Feat: implement output logic

[Uaitt]

In this PR I have implemented version 0.1.0 of aasm-rbs 🎉

Description

This PR contains:

• first implementation of the AaasmRbs module and Output class.
• unit tests for both entities.
• rename of the executable from aasm-rbs-generate to aasm-rbs
• reorganization of the Gemfile.
• configure Steep and add signatures.

Motivation and Context

How has this been tested?

With automated tests for both new entities.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.