Add documentations references for Valkey commands

[Aryex]

Overview

Users often searches for specific Valkey commands in the documentation to see how to use it through GLIDE. We should support this so that when a command is searched, it shows up with:

• A description of what it does.
• A small example in the selected language.
• A link to the method's API documentation.

Proposal

We are proposing to add new pages to our reference folder reference/commands. Commands will be organized into pages by their categories per Valkey's commands page.