Redis: add support for username and sentinel username fields

[ddubson]

Current implementation of Redis bindings does not support the spring.redis.username and spring.redis.sentinel.username fields, however these fields, while optional, are critical for connecting to Redis services in many cases. For consistency, spring.redis.sentinel.password should also be bound.

Proposal

Add spring.redis.username to be bound to {username}
Add spring.redis.sentinel.username to be bound to {sentinel.username}
Add spring.redis.sentinel.password to be bound to {sentinel.password}

References

• Common application properties
• Redis Sentinel support in Spring Data

[Kehrlann]

Related: #87