Pootle Fallback

As discussed in Slack, a fallback from localize.typo3.org to Pootle is required.

Desired Request Workflow

• TYPO3 backend will fetch transalation file from https://localize.typo3.org/ (e.g. https://localize.typo3.org/xliff/n/e/news-l10n/news-l10n-de.zip)
• localize.typo3.org is populated from Crowdin, when file found was found, deliver 1:1
• when not found, handle 404 through reverse proxy connecting to the same path on Pootle (https://extensions.typo3.org/fileadmin/l10n/n/e/news-l10n/news-l10n-de.zip)

Task

• add configuration to Git
• configure fallback flow
• check