Scalar quantization support

[trengrj]

Add support for new scalar quantization feature https://github.com/weaviate/weaviate/pull/5125 in 1.26

• Operates identically to product quantization

• Config struct and defaults are

{
  "vectorIndexConfig": {
    "sq": {
      "enabled": false,
      "trainingLimit": 100000,
      "rescoreLimit": 20 
  }
}