Support the customization of the timeout parameter when using a blocking connection pool with a redis cluster

[VincentHokie]

Pull Request check-list

• Do tests and lints pass with this change?
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Is there an example added to the examples folder (if applicable)?

Description of change

The timeout parameter is not one of the allowed redis keys, despite it being used for BlockingConnectionPool uses.

Because we need to let the RedisCluster configure its connection pools, we need to pass in the parameters that eventually make it to the creation of the connection pool.

Whitelisting the timeout key does this, and a test has been added to validate this.