JWT middleware: support for accessing token from cookie #589
Description
In addition to providing JWT by simple header or URL parameter there will be good to have possibility to get token from cookie.
As a bonus, it will be good to extend JWTConfig with HandleEmptyToken field of type echo.HandlerFunc - it will provide way to redirect to login page; other kinds of errors (as invalid token) should be handled without changes. Nil value should cause old behavior (400 - Bad Request).
This bonus will be backward compatible.
I will be glad to implement this myself and submit PR, but it is always good to ask for comments before doing so.