CRON: Control rate limit for update of Document article metadata

[jvwong]

Background:

Issue:

Details:

[jvwong]

This is only a problem (HTTP status 429) under rather artifical circumstances: Multiple, concurrent updates are fired. Practically speaking this would not likely happen as the CRON update interval is set to 1 week (i.e. it shouldn't take a week to update the docs).

For now, improve the overall logging detail and levels (debug vs info so we don't flood the logs).

See https://github.com/PathwayCommons/factoid/compare/iss1251_more-informative-error-logging?expand=1