[TASK] Handle multilingual-singledomain websites

[dogawaf]

Actually, we handle multilingual for multidomain websites.
This is easy because with differents hostnames, we can generate respectives 404.html files, which are then fetched by a READFILE:typo3temp/tx_static404-'.t3lib_div::getIndpEnv('TYPO3_HOST_ONLY').'.html instruction.

We need to handle multilingual 404 for singledomain websites, because they deserve too a proper static 404 handling.

Proposal

1. generate a 404.html file for each of the alternative page language. This is easy.
2. do some rewriting in the htaccess, by extracting the language path in the referer, and injecting it in the static 404 path.