Refactor Tabs component to use context api

`Tabs` should use context api to pass props to child components.

## Expected Behavior
Tabs should create a context provider and pass style props as well as click event handler and active tab index to child components.

## Current Behavior
Current implementation uses a method of mapping over children and cloning them with new props, this causes an issue when attempting to extend a component with `styled-components`. Rather than the underlying styled component receiving the new class attribute the whole component is wrapped in a new styled component which doesn't receive the props from the parent when the children are mapped.

## Possible Solution
Use context api to pass style props, `activeTabIndex`, `onTabChange` to child components. Each child should have a dom `ref` and check its own index to determine if the index matches the `activeTabIndex`.