Add animated submit button to contact form

[RobbieTheWagner]

We need to show users something happened when they clicked submit.

[hannakim91]

seems there is an animation on hover but not on keyboard tab-- will add this

[RobbieTheWagner]

I think this issue was meant to be adding a loading indicator or something to the contact form button, so people know something happened when the clicked it and don't click it multiple times.

[hannakim91]

I see - I made a separate issues since the hover color change was styled using different classes (added the keyboard/focus versions)