i18n for app interface

[kazup01]

If you're a native speaker of a language other than English, we'd love to see your contribution 🙂 It would be very helpful for people in your country!

• [x] English
• [x] French https://github.com/BoostIO/BoostNote-App/pull/1020
• [x] Chiense (zh-CN) https://github.com/BoostIO/BoostNote-App/pull/1033
• [x] Japanese https://github.com/BoostIO/BoostNote-App/pull/1065
• [x] Italian https://github.com/BoostIO/BoostNote-App/pull/1220
• [ ] You 👍 Feel free to leave a comment if you can contribute!

How to contribute:

1. Create a new file to /src/cloud/lib/i18n
2. Add the language option to /src/cloud/lib/i18n/index.ts, /src/cloud/components/settings/UserPreferencesForm.tsx and /src/cloud/lib/stores/settings/types.ts