This reverts commit f9e890176d.
It pulled updates from transifex *after* we switched translations
to 4.x only mode - which resulted in a lot of translation keys being
moved around. For example, asset-related translations went from
framework to the asset-admin module. The removal of these translations
in 3.x caused translations to go partially missing, since these new
modules are 4.x only.
See https://github.com/silverstripe/silverstripe-framework/issues/7002
The files are uploaded to transifex.com now, which means we needed
to consolidate the file names (= locales). Since Transifex doesn't allow
arbitrary JavaScript structures, we're using an intermediary JSON
format which gets transformed into the JS used by the framework.
See b59f3858af for generator logic.
Fixes https://github.com/silverstripe/silverstripe-framework/issues/2499
