Split form study details

[okaycj]

Summary

Fixes #327

This PR covers a few issues:

• Adds a sphinx development server to the make file and requirements.
• Update language around the "Create Study" button.
• Update screenshots of study details page.

[becky-gilbert]

Great!

[becky-gilbert]

Yay, thanks!

[mekline]

For examples like this where the new screenshot shows less content than the original, have you checked that the missing bits aren't referred to in the text? That is, making sure that the text doesn't talk about e.g. changing the study state when the screenshot now cuts off at the study link?

I think it's a good call to use these simpler screenshots with less content, just need to check that we didn't misplace any signposts as we do it!

[mekline]

(This was the other image I wondered about the text context for - I like the shorter screenshot, but check that the surrounding text doesn't assume that e.g. a pic of the exit url field is visible. If it does we probably just need to do some text massaging, let me know)