feat: react based studio footer

[KristinAoki]

This a rebuild of the current studio footer using React. The footer should have the same content as the existing footer.

For testing use course-authoring PR 532. The footer can be seen on at the bottom of Pages & Resources.

[connorhaugh]

Assumptions I have made for this review:

• The content/layout is correct (no mocks exist)
• You have made the choice to not put this in the footer library for a good reason.
• Code style is out of the window, as a lot of this is borrowed code.

[KristinAoki]

Assumptions I have made for this review:

• The content/layout is correct (no mocks exist)

Yes, content is matching the current footer in legacy studio. The coloring is set to match all the design patterns of the pages.

• You have made the choice to not put this in the footer library for a good reason.

I am following the pattern of not including the header in the header library.

• Code style is out of the window, as a lot of this is borrowed code.

@connorhaugh what do you mean by code style?

[connorhaugh]

@connorhaugh what do you mean by code style?

cleaner code, principally breaking jsx into smaller components to be more readable. Not the end of the world in this case if it makes things harder.