Combining with manual auth middleware

[JeronimoPaganini]

The reason why I've proposed these updates is case:

1. Would be awesome if we have Imperial OAuth + manual authentication middleware supporting
2. Also, if we gonna use just protectedMiddlewares group we shouldn't split out the oAuth and manual authentication middlewares.
   Example:

    let protectedMiddlewares: [Middleware] = [
        ImperialMiddleware(redirect: "/login/"),
        UserModel.redirectMiddleware(path: "/login/"),
        UserModel.guardMiddleware(),
        ActiveUserMiddleware()
    ]
    let authRequired = app.routes.grouped(protectedMiddlewares)
    authRequired.get("myProfile", use: profileController.index)

where UserModel.redirectMiddleware is Authenticatable.redirectMiddleware
And at this point, if a user has been manually authorized, ImperialMiddleware anyway will decline access to this route since the user hasn't accessToken.

If we use my proposed small upade, it might be used like:

    let protectedMiddlewares: [Middleware] = [
        ImperialMiddleware(redirect: "/login/",
                       onErrorMiddleware: UserModel.redirectMiddleware(path: "/login/")),
        UserModel.guardMiddleware(),
        ActiveUserMiddleware()
    ]
    let authRequired = app.routes.grouped(protectedMiddlewares)
    authRequired.get("myProfile", use: profileController.index)

where onErrorMiddleware is optional and works only in the case if accessToken doesn't exist.

If I've made something overhead and we have a better solution for the case, please let me know :)