HNSW BQ dimension tracking

[trengrj]

What's being changed:

With the newly introduced HNSW BQ feature we also need metrics which are used for billing / sizing to reflect this.

• HNSW BQ will cause an 8x reduction to vector_segments_dimensions
• DimensionCategory type created for easier extension in the future
• Additional tests were added that directly inspect prometheus metrics
• Typo fixed for resetting PQ vector_segments_dimensions when a class is deleted

Review checklist

• Documentation has been updated, if necessary. Link to changed documentation:
• Chaos pipeline run or not necessary. Link to pipeline:
• All new code is covered by tests where it is reasonable.
• Performance tests have been run or not necessary.

[sonarcloud]

Quality Gate failed

Failed conditions
59.6% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud