Registered contractor can browse RFPs

[rkim00]

As a registered contractor, I want to be able to browse RFPs (i.e., see all RFPs), so that I see how many and what kinds of RFPs are in the platform, and find RFPs to apply to.

If easy, it might be nice to have some links that will show RFPs by market and/or type, either by filtering or by going to different page.

This story will also require a member being able to log in if not already logged in. See mock-ups for one implementation example: https://drive.google.com/file/d/1-ERKKr72JosM7mvIvafwInl0xYhflQun/view

See also #6, #8 .