Harmonize naming of session repositories

[vpavic]

This is a follow up task on #1408 - we should consider renaming SimpleRedisOperationsSessionRepository to something more meaningful but also take a look RedisOperationsSessionRepository naming.

[vpavic]

While trying to figure out a more suitable and descriptive name for SimpleRedisOperationsSessionRepository we've decided to expand this issue to harmonize naming across all the session repositories.