Ensure that the crowdin cache directory exists.
Use "https" for Crowdin API url instead of "http" and set as a constant for code re-use.
Concatenate .po files from Crowdin's "versioned" folder only if they are the same version as the server.
Remove the "kalite-<language_code>" path because it's not used during concatenation of .po files.
Merge pull request #215 from mrpau/feature/210-extend-update_language_packs-to-only-build-the-right-po-file-per-version

Feature/210 extend update language packs to only build the right po file per version