Move redis session to it's own project

[piraz]

Relocate the current Redis session management implementation from the main candango/httpok project into a dedicated repository. This change is intended to remove the Redis dependency from the core project, keeping candango/httpok lightweight and allowing users to opt-in to Redis session support only if needed.

Tasks

• Identify all code and dependencies related to Redis session management in candango/httpok.
• Create a new repository (e.g. candango/redis-session or similar).
• Move the Redis session code and tests to the new repository.
• Update import paths, documentation, and package names as appropriate.
• Remove Redis dependencies and references from the candango/httpok project.
• Add notes to the candango/httpok README and documentation indicating where Redis session support can be found and how to integrate it.

Acceptance Criteria

• No Redis dependencies or session-related code remains in the main candango/httpok repository.
• The new Redis session repository contains all relevant code and passes tests.
• Documentation in both repositories is updated to reflect the migration and integration steps.
• candango/httpok builds and operates successfully without Redis session support.

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