feat: Add support for boolean `ssl.verify` in SchemaRegistryClient

[allamiro]

• Added support to use boolean ssl.verify in SchemaRegistryClient to simplify SSL verification handling and troubleshooting.
• Enforced ssl.verify to accept only boolean values (True or False) to toggle SSL verification.

Motivation:

• This pull request introduces a dedicated ssl.verify parameter to the SchemaRegistryClient configuration, enabling users to simplify SSL verification without directly manipulating the _RestClient class.
• These changes improve usability, align with Python best practices, and ensure clearer configuration handling.

  Impact

• These changes simplify the API .
• Documentation: Updated to reflect the changes in SSL configuration parameters.

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[rayokota]

Thanks for the PR. We'll be moving to httpx, and we'll be exposing the verify parameter to the httpx client.

[allamiro]

Thanks for the PR. We'll be moving to httpx, and we'll be exposing the verify parameter to the httpx client.

If my contribution simplifies your transition or adds some value, i would hope that you consider merging it as a temporary improvement to the current client program.