Implement basic components for the UI Kit

[eluciano11]

Implement the basic components that we will in the UI Kit that will help us create the new website designs.

Components:

• Buttons with variants, sizes and icons.
• Text with variants and sizes.
• Form fields with labels, input fields, checkboxes, etc.
• Links with variants.
• Toasts.
• Modals.
• Grid system (consider using rebass grid? https://github.com/rebassjs/grid)