[Feature Request] Support Markdown with metadata

[grgprarup]

What do you think about adding support for Markdown files with metadata? Metadata might be in yaml format or any other key-value format. Each slide will be rendered with provided content and data (like images) in metadata according to the template type defined in slideType.

Feature Objective: Render each slide according to the template (layout) and make uniformity while creating training or official presentations in an organization.

Below is the template of the Markdown file with metadata. The given template might not be a proper way but my target is to achieve the Feature Objective.

metadata:
  - slideType: title-page
    images:
      - examples/assets/logo.png
  - slideType: text
  - slideType: text-image-image
    images:
      - examples/assets/image1.png
      - examples/assets/image2.png
  - slideType: image
    images:
      - examples/assets/image1.png
  - slideType: thank-you-page
    images:
      - examples/assets/image1.png
---
# Title of Presentation
### Name of Presenter
---
# Text Title Goes Here
Content goes here
---
# Text-Image-Image Title Goes Here
Content goes here
---

---
# Thank You

Some Template Screenshots:

[danielb2]

https://github.com/webpro/reveal-md this lib is already using a frontmatter. maybe this helps someone