Add authors contacts to articles

[DecoyRS]

Create DB of authors in _data with links to social networks.
Example:

// authors.db
- name: Name Surname
  connections:
  - GitHub:  https://github.com/DecoyRS
  - Slack: https://thetoolsmiths.slack.com/messages/D4R0RB5FT/

// social_networks.db
- GitHub: assets/icons/GitHub.png
- Slack: assets/icons/Slack.png

This information should show up on the page as icons for corresponding networks, e.g. GitHub - OctoPuss, Slack - "Slack's hashtag symbol" with link to Toolsmiths slack with direct message link to the author, etc.