Added ret. val. checking, db export per-source file generation (#7155)

In export_database.download_source_data(), added check for the return
value of store_result_into_file(), so that, if it has failed, the
file does not get uploaded to the CDN.
Update ingestion server setup instructions in README
Add scdl_type_from_format module

- Add units tests for new module
- Update SCDL profiles to use new module
Merge remote-tracking branch 'origin/develop' into 7197-add-mdl-type-mappings
Added default type to enrich-type module

This allows individual providers to have default types for items
whose types can not be determined.
Also added default type of "text" to Minnesota profile.