Add Modal component

[idelmr]

Description

Add custom Modal component to:

• Control zIndex (priority) of multiple modals: Higher (larger magnitude) priorities would render on top of lower priority modals or screens
• Add onHide callback to hide Modal when the backdrop or the Android back button are pressed (also customizable with given props)
• Give access to Modal inner styles to avoid unnecessary children styles

Missing: Animations (slide from middle, slide from bottom, and fade)

Types of changes

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

Checklist:

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