- Doc that describes the steps to add a new language  to Spacedeck Open
- New file with translated entries for using in Spacedeck Open in Spanish
- Include 'es' as new locale in Spacedeck Open
- Include a radiobutton for users could select the new language

* 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>