Front-end changes for custom landing page (Thomas/150908)

[thomaswhyyou]

• Edited urls.py for custom landing page at root url
• Added views.py with corresponding view for root url
• Added templates/ and static/ folder for html and css for the new landing page

[geoffscott]

@thomaswhyyou: looks great, except can we first merge into staging so we can see this deployed before merging into master?

[thomaswhyyou]

Closing this PR to master, and instead will make a new one to staging first.