Reduce logging to Sentry

[agjohnson]

We're error logging a number of things that shouldn't be error logs. This pollutes Sentry with a number of issues that aren't really our issue (build failures on pip/etc). We should clean up our logging here to reduce noise and get back to a reasonable number of logging events.

[humitos]

I'm linking some work that has done outside this issue.

Related PRs: #4779 #4761 #4760 #4730

Issues: #4791 #4790 #4590

This one, can be closed soon. In theory, after the following deploy, we will decrease the spam-logging into Sentry a lot.

[humitos]

Maybe this setting can be used to do not log known exceptions to Sentry on Celery tasks:

https://docs.sentry.io/clients/python/integrations/django/#additional-settings

[humitos]

http://docs.celeryproject.org/en/latest/userguide/tasks.html#Task.throws