Have Markdown files with YAML data show the YAML as HTML Table (like Github)

Adding this issue just because I'm working on it and have a PR ready for it. Simply needing Gogs to support YAML data at the top of a Markdown file, marked by a --- at the beginning of the file and at the end of the YAML, just like Github does. Example:

---
language: en
module: translation_checking
author: Jim Smith
version: 1.2

---
# Translation Checking
## How to check

This is the text

This can easily be done with the go-yaml parser, which knows how to find the YAML and make a map from it.

Github allows for YAML at the top of a Markdown to be displayed in an HTML
table when viewing the file.

See: https://github.com/blog/1647-viewing-yaml-metadata-in-your-documents

Example on Github:
https://github.com/unfoldingWord/unfoldingWord.github.io/blob/master/pages/content/tn.md

Imports: https://github.com/go-yaml/yaml

The issue names no repository files or tests; start by locating Gogs's Markdown file rendering path and reviewing the proposed go-yaml import. Use the supplied YAML-front-matter example to verify that the metadata is rendered as an HTML table while the remaining Markdown remains visible.