Lazy load translations

[danimoh]

Lazy load requested translations instead of bundling them all.

Things to keep in mind:

• Translation files should be fetched with an integrity checksum. This is supported by fetch directly. The hashes would need to be generated during build and bundled with the common snippet.
• The checklangs script will need to be updated.
• What to display until language is loaded? Keep the loading spinner spinning until language loaded? Or bundle English and display English first but translations manually translated via translatePhrase then do not update reactively.