User authentication middleware/controller

[bunsenmcdubbs]

• [x] Account creation
• [x] Password encryption with bcrypt and checking if they match
• [x] Login (JWT creation, parsing and validating)
• [x] Authentication middleware to protect routes (includes redirects)
• [x] Unit tests
• [ ] (extra credit) Password reset

Relevant routes from #58 (to be finalized):

Route	Method	Description	Request	Response
/user	PUT	Create a new user	{email: <string>, password: <string>, org_id: <id>}	{token: <JWT>}
/user/login	POST	Login and authenticate	{email: <string>, password: <string>}	{token: <JWT>}

blue-jay/blueprint is a good template for MVC golang servers. I've used as a reference to structure a much of this project. In particular, something like https://github.com/blue-jay/blueprint/blob/master/middleware/acl/acl.go would probably be the way to go.

This middleware would be selectively applied to routes by wrapping around the route's http.Handler similar to how it works for the logging and recovery middleware https://github.com/HackGT/SponsorshipPortal/blob/master/server/routes.go#L26-L27