Build login and register pages

[briri]

Update the current login and register placeholder pages, at /signup, and /login, so that they look like current wireframes.

We can skip the first page for now. It asks the user for their email and attempts to determine if they have SSO available. We won't have SSO for a while, so we can add that in at a later date.

Login page:

For now, the forgot password link can just display a to be built message since we need to add this capability in the AWS environment.

The get help link can go to a blank page for now or just display a to be built message

Register page:
We can build this initial register page since its the page that leads to the "Create Account" page, but the SSO button does not need to do anything at this point.

Note that the query behind the affiliation/Institution field typeahead is slow at the moment. We have a ticket #67 to address this. For now, stick with searches for institutions that appear earlier in the alphabet (e.g. Alaska, Canada, etc.)

The User schema and model need to be updated to accept the acceptedTerms boolean. See issue #93

This work is related to issue #116