[Feature] Be able to directly upload post images to the database using the post editor

[3vorp]

Is your feature request related to a problem?

Adding a post header image to the database is quite a clunky process and prone to human error.

Describe the feature you'd like

Similar to the add-on form, use a drop zone/file picker to be able to add a header image to the database directly.

Screenshot(s)

No response

Notes

To maintain backwards compatibility we should probably not use files.json and instead just upload the URL as part of the post json