fix(redis): mitigate JedisPool depletion (#419)
* chore(dependencies): gradle 5.4.1
* fix(redis): mitigate JedisPool depletion
Fixes redis interactions in RedisPermissionRepository that can result in
depleting the redis pool.
Specifically:
* converts smembers calls to sscan calls, and gets/returns an object
from the pool to do so.
* removes nested calls to redisClientDelegate that were holding on
to pool objects
* partitions lookup of users into smaller batches
* partitions role lookup
Additionally, uses InstrumentedJedisPool to enable metrics collection
on redis interactions.
