Merge pull request #1430 from diox/document-translations-app

Document translations app internals (bug 942185)
Merge pull request #1466 from diox/collections-slugs-in-URLs

Allow slugs for every endpoint in collections API (bug 918035)
Merge pull request #1500 from diox/improve-api-translations-docs

Improve documentation about translations in API  (bug 946738)
Disable ENABLE_API_ERROR_SERVICE on jenkins for now