* Use [node-]redis as a direct dependency
* Extract Redis client creation to its own module
* Attach extensive logging in the Redis client creation module
* Allow the rate limiter to pass requests when Redis is disconnected
* Update rate-limit-redis
* Default error input to empty object for formatRedisError method
* Provide a name for the rate limiter's Redis client
* Include redis-mock, exclude ioredis/ioredis-mock
* Remove unused RedisAccessor#exists method
* Switch RedisAccessor to use redis/redis-mock
* Provide a name for logging on the Redis page cache
* Remove extraneous trailing space from Redis logging prefix
Our updated use of console.* will already be adding a space after the prefix
* Replace ioredis-mock with redis-mock in tests
* Revert removal of ioredis dependency
* Bind Redis client to async promisified methods
* Extract former RedisAccessor constructor tests to new create-client tests
* Update RedisAccessor tests to work with the callback-based redis client
* Handle formatting Redis errors (or not) with more resiliency
