Require login to connect to staging (#1360)

## Description:

Complete:
- Add support for cookie-based auth (ref
https://github.com/openfrontio/infra/pull/83)
- Restrict game server API access to users with a specific flare
- Restrict join game to users with a valid token and an allowed flare
- Unauthorized landing page
- Token cache
- Destroy token cookie on logout

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

tests/util/TestServerConfig.ts

@@ -4,6 +4,9 @@ import { GameMapType } from "../../src/core/game/Game";
 import { GameID } from "../../src/core/Schemas";
 
 export class TestServerConfig implements ServerConfig {
+  allowedFlares(): string[] | undefined {
+    throw new Error("Method not implemented.");
+  }
   stripePublishableKey(): string {
     throw new Error("Method not implemented.");
   }