Feature Request: Add labels to published pages

[jannismain]

Extend yaml frontmatter parsing to read labels key:

---
title: Page Title
labels: [label1, label2]
---
...

Apply those labels to confluence page after creation. When updating pages, I would probably delete existing labels from the page and apply those listed in yaml frontmatter, to ensure they are in sync with the labels listed in the markdown file.

[jannismain]

For my personal markdown writing preference, I would also like to support listing labels in the document like this

# Page Title

#label1 #label2

This page has labels.

However, this is custom markdown syntax. How do you feel about introducing support for something like this in md2cf?

[iamjackg]

Custom markdown syntax is kinda messy with Mistune, it's something we could consider in the future, but for now I'd rather keep these in the frontmatter if that's okay.