proposal: stabilize `std/media-types`

[iuioiua]

Package documentation: https://jsr.io/@std/media-types/doc

Progress:

• [x] 100% documented, passing deno doc --lint checks and adhering to the documentation guidelines.
• [x] Maximum possible test coverage
• [x] No open issues or pull requests that might lead to breaking changes. For example, issues that suggest new non-breaking features are fine to exist at stabilization.
• [ ] Publish 1.0.0-rc.1
• [ ] Wait 1 month for feedbacks
• [ ] Publish 1.0.0

Towards #4600