Redis to valkey (examples)

[rukai]

The final PR for "redis" -> "valkey" renaming:

• renames usage in examples documentation
• renames a few usages in the codebase
• swaps a few docker images from redis to valkey
• I removed the benchmark results from redis-clustering-unaware.md since they are likely very out of date at this point.

[codspeed-hq]

CodSpeed Performance Report

Merging #1850 will not alter performance

_{Comparing rukai:redis_to_valkey_final (43c0e0c) with main (de0d1a3)}

Summary

✅ 38 untouched benchmarks