Docs Folder (#84)

* Initial documentation folder with instructions on adding fonts.

* fixed markdown syntax error

* Update adding_fonts.md

Added some links to the referred code lines and fixed some formatting.
Co-authored-by: mntmn <lukas@mnt.mn>

docs/adding_fonts.md

+To add fonts to Spacedeck Open, follow these steps:
+
+1. Find the googleapis link for the font and add it to [./styles/type.scss](https://github.com/spacedeck/spacedeck-open/blob/docs/styles/type.scss#L4) after the `Inter` font that is already there. Here is a good reference to using [Google Font API](https://www.webfx.com/blog/web-design/google-font-api-guide/).
+2. Add the name of the font to the file [./public/javascripts/spacedeck_sections.js](https://github.com/spacedeck/spacedeck-open/blob/docs/public/javascripts/spacedeck_sections.js#L150) in the `fonts` section found around line 150. The order of the list here is the order in which fonts will be displayed in the user interface.
+3. From the root of your install, do `gulp styles` to recompile the SCSS.
+4. Restart your server.