Add Redis Stack support as a Herd service

[bnomei]

Herd currently bundles and manages standard Redis as a local service. 

Please add support for Redis Stack (Redis with modules like RedisJSON, RediSearch, etc.) as an optional service in the Herd services list. This would let developers spin up a Redis Stack instance directly via the UI/CLI without external tooling.

Why
• Redis Stack modules are increasingly used for search/JSON/graph workloads.
• Running Redis Stack outside Herd (Docker/Homebrew) breaks the cohesive local stack experience.

What to include
• A redis-stack service option.
• Bundled modules (JSON, Search, etc.) with config/UI controls.
• Version selection consistent with other Herd services.

Happy to help test or provide feedback.