Import & Export language as ZIP

[Kirby]

Right now, languages can only be exported and imported as XML.

This needlessly complicates the process for those that provide Language Packs / Translations and those who use them:

1. Start export as XML
2. Transfer compression (gzip/brotli) by most origin server / CDN if supported by client
3. Transfer decompression by client (if compressed)
4. Create ZIP
5. Upload ZIP for distribution (in xenforo.com Resources, etc.)
6. Download ZIP
7. Extract XML from ZIP
8. Start uploading XML
9. Transfer compression by client (if supported by orgin server/CDN)
10. Transfer decompression on origin server
11. Finally: Import XML

Steps 1-5 are performed by those creating language packs / translations, the remaining steps are executed by those who use them.

So there is a lot of (manual) compression / decompression going on here so my suggestion ist to support export & import as ZIP which cuts down the process to

1. Start export as ZIP
2. XenForo builds the XML and creates the ZIP in one step
3. Upload ZIP for distribution (in xenforo.com Resources, etc.)
4. Download ZIP
5. Start uploading ZIP
6. XenForo extracts the XML from the ZIP and imports it in one step

=> Only one compression and one decompression which happens automatically.