fix: Improve handling of suspended users signing in with email (#2012)

* chore: Separate signin/auth middleware
fix: Email signin token parsed by JWT middleware
fix: Email signin marked as active when logging in as suspended
fix: Suspended email signin correctly redirected to login screen
closes #1740

* refactor middleware -> lib

* lint

server/types.js

@@ -1,6 +1,6 @@
 // @flow
 import { type Context } from "koa";
-import { User, Team } from "./models";
+import { User } from "./models";
 
 export type ContextWithState = {|
   ...$Exact<Context>,
@@ -10,13 +10,3 @@ export type ContextWithState = {|
     authType: "app" | "api",
   },
 |};
-
-export type ContextWithAuthMiddleware = {|
-  ...$Exact<ContextWithState>,
-  signIn: (
-    user: User,
-    team: Team,
-    providerName: string,
-    isFirstSignin: boolean
-  ) => void,
-|};