Add support for sentinel password

[BjoernHelmbold]

Currently if you have authentication enabled for sentinel the application cannot get master information

Description

If you want to use Sentinel with authentication the plugin currently cannot connect to the Sentinel.
With this change it is possible to support the same password as the Redis itself uses.

Steps to Replicate the Issue

1. Setup up Sentinel with auth
2. Try to connect to Sentinel

[snake14]

Thank you for taking the time to create this PR. I requested one small change.

[snake14]

Apologies. I just thought of a couple more change requests.

[snake14]

@BjoernHelmbold Thank you for making the requested changes.

Apologies for taking over your PR. I got looking into how to fix the broken builds and realised that always using the password could break functionality for any customers using a password for their Redis master, but not their sentinels. I added a new setting to protect against that.

[snake14]

Aside from the UI test failures, I think this is good to go. The failures are because I added a new setting. CI isn't saving the screenshots, so I'll see if I can generate some locally.

[snake14]

@AltamashShaikh Can you please look over the latest changes. I think everything is good, but I'd like a second opinion.

[AltamashShaikh]

Looks good to me 👍
I can see the new setting appears only for redis section

[snake14]

Thank you again for taking the time to create this PR @BjoernHelmbold . Your contribution is appreciated.

[BjoernHelmbold]

Thank you very much. The solution goes in the direction of one of my open issues which would support to set different credentials for redis and sentinel any ways.