Update translatable strings

modified:   src/app/language/en.json
modified:   src/app/templates/about.tpl
modified:   src/app/templates/settings-container.tpl

- Changes strings in "about.tpl" and "settings-container.tpl" into translatable strings
- Adds the new translatable strings in "en.json"
- Fixes line 149 in "en.json" to fit with the actual string in "settings-container.tpl"