Introduce credentials provider (#3224)

[kimmking]

References:

1. Request New Feature: allowing the ability to reset password during runtime for Jedis's auth redis/jedis#1602 and related PRs. Current PR is probably better than handling in JedisFactory
2. CredentialsProvider class added to support password rotation redis/redis-py#2261 - main reason of this PR
3. Password Rotation support - Add a CredentialProvider interface/class and set your own provider redis/lettuce#1774
4. Security Flaw In How Jedis Stores Server Password redis/jedis#632

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• Introduce credentials provider

• use volatile

• Test in Sentineled mode

• Support CharSequence in DefaultRedisCredentials

• Added doc for prepare() and cleanUp()

• Test the provider interface

• Added example

• Removed deprecations