prosemirror: fix embedded saving

The node type wasn't saved back correctly from the form.

prosemirror cleanup and singleton form

Some initial cleanup of the form class. It's now a singleton.

Handle titles and dimensions in prosemirror

proper differentiation between mediafile and embed in prosemirror

initial work on making embedded diagrams work in prosemirror

Fix indentation

refresh diagrams in prosemirror after editing

remove unnecessary resolveImageAttributes

No need for an Ajax roundtrip

simplify node view

Use img to render, remove wrapper

Add edit button in Prosemirror

Select files in media manager in Prosemirror

Simple Prosemirror menu button and edit form

Attach Prosemirror schema when API is initialized

Rudimentary prosemirror support (as yet only view)

Remove the SVG Sanitizer again in favor of CSP headers

This introduces a renderer that allows us to call each embedded SVG as a
separate URL with added CSP headers. This way we rely on the same safe

Remove the SVG Sanitizer again in favor of CSP headers

This introduces a renderer that allows us to call each embedded SVG as a
separate URL with added CSP headers. This way we rely on the same safety
feature as with media file based diagrams.

show more ...

style fixes

fix media manager integration with deferjs disabled

refactor the media manager integration

refactored action components

more strict separation of modes

more refactoring for mediafile diagrams

Editing of embedded diagrams works now

Embedded diagrams can be added and edited directly in the editor or
edited when viewing a page

Editing embedded diagrams now works

first round trip editing for mediafiles works with new class

Add ajax backends for loading/saving embedded SVGs

This also renames the syntax classes to be easier to distinguish

more work on the new DiagramsEditor class

Loading now waits for the init message. Things like reloading the
mediaManager can now be done in the postSaveCallback