docs: add write org endpoint rate limits

[hazel-nut]

Description

adds write org endpoint rate limits.

also converts the HTML on the page to markdown. commits are descriptive.

References

DR-2720

Checklist

• I've read and followed CONTRIBUTING.md.
• I've tested the site build for this change locally.
• I've made appropriate docs updates for any code or config changes.
• I've coordinated with the Product Docs and/or Docs Management team about non-trivial changes.

[github-actions]

Summary

Status	Count
🔍 Total	36
✅ Successful	24
⏳ Timeouts	0
🔀 Redirected	0
👻 Excluded	12
❓ Unknown	0
🚫 Errors	0
⛔ Unsupported	0
Full Github Actions output