[DO] Updating Durable Objects storage API docs

[Oxyjun]

Summary

We're updating the way we present DO Storage API to clearly delineate between the older API for KV-backed DOs, and the newer APIs for SQLite-backed DOs.

1. Previous "Durable Object Storage" chapter has been split into:
   • "KV-backed Durable Object Storage (Legacy)"; and,
   • "SQLite-backed Durable Object Storage".
2. Both of the two new chapters start with the same introduction, explaining the differences between the two.
3. Both pages start with a note component that identifies whether the page is for SQLite-backed DOs or KV-backed DOs.
4. Repeated text (e.g. Alarms, Other methods, etc) has been put into partial files.
5. Pending The KV API for SQLite DOs have been modified to reference the new synchronous KV API.
6. All of the links have been updated to the most logical route. Unless explicitly required, all links will direct to sqlite-storage-api.

Screenshots (optional)

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The documentation style guide has been adhered to.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• Files which have changed name or location have been allocated redirects.

[github-actions]

This PR requires additional review attention because it affects the following areas:

Redirects

This PR changes current filenames or deletes current files. Make sure you have redirects set up to cover the following paths:

• /durable-objects/api/storage-api/

Partials

This PR updates partial files, which are pieces of content used across multiple files in our Render component.

• durable-objects/do-faq-limits - view affected files
• durable-objects/do-faq-pricing - view affected files
• durable-objects/durable-objects-pricing - view affected files
• durable-objects/durable-objects-sql - view affected files
• durable-objects/recommend-sqlite-do - view affected files
• durable-objects/storage-intro-text - view affected files

[lambrospetrou]

This is also not a concern with the Iterable unless the user reads the whole thing and stores it in memory. Not sure if we need to change this, but it's a bit different than the eager array result.