Final NR clean-up tasks

[robrap]

There may be some discovery on the final set of tasks here, but this ticket is for final clean-up of New Relic within 2U. The openedx/edx-django-utils will still have a supporting backend.

Here is a partial list:

• Does our forked hacked new relic tracing library still exist? We are blocked on clean-up until that work is complete, but otherwise, ensure it is archived.
• MFE configs still include NEW_RELIC_* settings. Do we have other New Relic settings?
• Ensure traffic is no longer being sent to NR for all services (including Insights, etc.)
• Clean up edx/configuration repo and references to New Relic.
• Do we want to remove the IGNORED ERRORS functionality from edx-platform? This would probably follow the DEPR process.
• Do we want to close down the NR account, or is it useful to still be able to log in? Will we not be charged if there is no usage?

[robrap]

Includes:

• Clean up edxapp newrelic config to .ini #493

Blocked on:

• Disable NR everywhere asap to reduce costs #701