New table for supported indexes

[prrao87]

We currently list all our supported distance metrics here. This is quite helpful to understand the difference at a glance.

However, for the vector index page, we don't have a table that lists (concisely) all the available in index.py via our Python API.

Food for thought items too:

• Are we organizing content in the "Indexing data" vs. "Building queries" sections well? If a user wants to find the supported distance metrics, they need to go the "indexing" section, but if they're looking for the list of supported indexes, they are described in the "vector search" page. Kinda confusing from an organizational perspective 😕
• Check if these indexes are exposed in Rust/TS too 😅 - if they're not, we'd have to phrase it accordingly in the table