Collection of issues in other tools we depend on

[nkuehn]

• add "continue on problems" parameter commercetools/sphere-category-sync#12 (continue on problems in category import)
• Consider using the streaming API for parsing CSV (> v0.4.0) commercetools/sphere-node-product-csv-sync#56 csv-product-sync fails hard due to CSV file size.
• Use externalId for category mapping commercetools/sphere-node-product-csv-sync#52 (product csv import should be able to map categories by external ID)
• categories mapping creates invalid JSON commercetools/sphere-node-product-csv-sync#83 (category references broken)
• find a web frontend that supports deeply nested category structures

Workaround possible / not a hard blocker (it would just be nice if the stuff would take less than the current 2-3 hours to run):

• Cope with unordered CSV files commercetools/sphere-category-sync#6 (category import requires tree-ordered import files) -- Workaround possible by doing a two-pass import, first flat and then update with tree info)
• Support recognition of related variants by configured attribute column commercetools/sphere-node-product-csv-sync#37 (product csv import should detect variants itself)
• groupColumn cannot be a column added by the mapper sphereio/csv-mapper#1 (csv-mapper requires a group column, but that cannot be created in the same run so we have to run through the mapping two consecutive times with separate mappings)
• Improve memory efficiency of lookup in external CSV files sphereio/csv-mapper#5 (csv-mapper bombs node memory with many external csv lookups)

[nkuehn]

@mmoelli I cleaned up this list and added the csv importer issue.