login controller

[warthogs32]

• [x] create login controller

• [x] message handler

• [x] appropriate DTOs

• [x] test

https://github.com/seanonline/Webapi_JWT_Authentication/blob/master/WEBAPI_JWT_Authentication/WEBAPI_JWT_Authentication/Models/Models.cs

http://www.decatechlabs.com/secure-webapi-using-jwt