Add REDISMODULE_KEYTYPE_STREAM Edit RM_KeyType and RM_ValueLength to handle a stream key

Comment From: madolson

I'm going to close this in favor of tracking this here in the original more complex request: https://github.com/redis/redis/issues/5760

Comment From: oranagra

it's already done in https://github.com/redis/redis/pull/6547. just forgot to close it