Support adding multiple media files to a post without JavaScript

[paulrobertlloyd]

Is your feature request related to a problem?

It is not possible to add multiple media file paths/URLs to a post unless JavaScript is enabled:

With JavaScript:

Without JavaScript:

Describe the solution you’d like

Always show the ‘Add another [media type]’ button, and have it make a server request that reloads the page with +1 media input fields shown, while keeping any previous values entered.

This request should not make any requests to the Micropub server.