fix(download): Respect `missingFilesAreFatal` parameter
fix(download): Respect `missingFilesAreFatal` parameter

The OpenAddresses download did not include error handling that took the
`missingFilesAreFatal` parameter into account. Therefore, all download
errors stopped the entire download process.

Especially for large areas that include many of the individual OA files,
gracefully skipping files that have download errors can be a convenient
way to handle sources that are having issues.

Fixes https://github.com/pelias/openaddresses/issues/425

pelias/openaddresses,pelias/openaddresses