feat: add insert benchmark

[edwinkys]

Purpose

This PR adds a benchmark to measure the collection insert operation. This is the result I got from running it locally on Apple M2 CPU with 16GB of RAM:

• Collection size: 1,000,000 Vector dimension: 128 Insert performance: 45ms

Testing

• [x] I have tested this PR locally.
• [x] I added tests to cover my changes, if not applicable, I have added a reason why.

Chore checklist

• [x] I have updated the documentation accordingly.
• [x] I have added comments to most of my code, particularly in hard-to-understand areas.