refactor Flex component

[gesquinca]

Is your feature request related to a problem? Please describe. Flex and Box components are basically identical and this flexibility makes it hard to determine when to use each.

Describe the solution you'd like Box should have the properties of the "box model" while Flex should have the properties of the "flex-box model".

Additional context https://styled-system.com/table#flexbox

Acceptance criteria:

• Flex component should have properties for flex-box model

E: 1/2 D