Add blog on binary vector support in KNN

[heemin32]

Description

Add blog on binary vector support in KNN

Issues Resolved

https://github.com/opensearch-project/project-website/issues/3417

Check List

• [X] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the BSD-3-Clause License.

[dylan-tong-aws]

I've reviewed the blog. It looks good in terms of content.

[heemin32]

@pajuric Please review this PR.

[kolchfa-aws]

@pajuric: I've addressed editorial comments. Could you review/update the meta for this blog, and it'll be ready for publishing.

[nateynateynate]

Pushing to staging.