Finished multi-lingual implementation

- Updated README to accomodate for changes
- Updated footer and roadmap for multi-lingual readiness
- Updated yml files for an 'untranslated' string
- Added an 'untranslated' snippet to all untranslated files
- Added a 'template' language for new languages to be made easily
- Added link to Monerujo site to Downloads page
- CSS updates