Finalize uploader

[nbumbarger]

Combine four PRs to update develop branch.

• Convert layout to match wireframes.
• Add success and failure messages.
• Add better validation summary information.
• Add e-mail field and attaches e-mail column to CSV data.
• Add form validation.
• Add instructions/ schema definition modal.

[danielfdsilva]

@nbumbarger

• Form clears well on cancel
• When the submission errors because of an invalid token, the Try Again button resubmits the form which will never work. This should be handled in a different way. Maybe redirect to the 1st step?
• If I try to submit data with a valid token, the call to https://api.openaq-staging.org/v1/upload returns 200 but I still get the "Uploader Error" screen.