Mathematics node bloats the largest chunk including katex twice

[max-nextcloud]

Describe the bug
The current mathematics implementation imports katex three times:

• via @tiptap/extension-mathematics

• via markdown-it-katex

• directly.

• We add a custom node view so the katex part in the tiptap extension never gets used - it's imported never the less.

• Markdown-it-katex will render the latex and then we extract its source from the annotation tag.
  We could avoid the entire rendering in the first place and thus also the katex dependency.

• Make sure to lazy load katex our in the node view only if latex is actually used on the page.