Token TTL configuration

Issue

I am running into frequent OOMKill issues when running redis as a storage backend. A little investigation shows, that no TTL is set on any keys written into redis.

Details:

• redis:8.2.3
• whiteboard:v1.3.0

Analysis

Digging into the code I found a setting CACHED_TOKEN_TTL that was introduced in #306 . The setting still exists in the websocket_server/Config.js however, it is not used anywhere in the code anymore. It seems like this refactoring (#393) reverted the usage of this setting. I was not able to find any explanation or mention on why this was removed.

Proposed Solution

Reintroduce the handling of the CACHED_TOKEN_TTL in the ServerManager class as in #306:

		this.cachedTokenStorage = Config.STORAGE_STRATEGY === 'redis'
			? StorageManager.create('general-redis', this.redisClient, null, { prefix: 'token_', ttl: Config.CACHED_TOKEN_TTL / 1000 })
			: StorageManager.create('general-lru', null, null, { ttl: Config.CACHED_TOKEN_TTL })