Adding ability to specify additional pandoc arguments in the frontmatter

[jvsteiner]

Hi, I made a request about this recently in issue #212 - it was super easy to do, so I went ahead and made a PR. Hope you like it.

[jvsteiner]

it works like this, now you can add them into the note's frontmatter like so:

---
additional-pandoc-arguments:
  - --template eisvogel
  - --filter=scripts/filter.py
---

[jvsteiner]

In case anyone is interested, here is some templates I use that show how I use this feature: https://github.com/jvsteiner/pandoc-obsidian-templates