Adding example modal component

[HannesAlexandersson]

Adding a complete modal component to showcase the structure of the library beter. it is complete with documentation and instructions on usage

Description

Adding a new component. a modal that after activaded opens a overlay over the main content and can be closed with an "X" button. it comes with a separate css and js file aswell as component specefik documentation.

Related Issue

This PR closes #8 on merge

How Has This Been Tested?

Tests have been performed by running the files locally.

Checklist

• My code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have tested my changes and confirmed that they work.
• I have updated the documentation (if necessary).

Additional Information

no further information needed