Added phpredis sentinel auth

[McFistyBuns]

Updated the PhpredisClientFactory to allow for password authentication when using redis sentinel. The default is to use the password set in the parameters password configuration, but also allows for an override in the dsn.

https://github.com/snc/SncRedisBundle/issues/697#issue-1578053433

[ostrolucky]

I've worked on this, but I realized this approach cannot work as is, because it requires having same password on both: sentinel and redis servers. In case somebody had password on redis servers only and sentinel unprotected, this change will attempt to auth the sentinel now and connection will fail. Needs some rethinking.

[ostrolucky]

Predis also doesn't support this https://github.com/predis/predis/issues/594 And they have a same concern as I have pointed out: username/password cannot be reused for sentinel, there should be different configuration. And at this point I don't really want to introduce it, because if we introduce new option and later predis introduces separate one, it will most likely be a different option and we would then have to support both :/