Revisit and clean up Sentry integration

[Mr0grog]

In #213, I am upgrading Sentry to v2. We have a few hacks around it in the diff server that I don’t think are still necessary, but which are not causing problems. These should be revisited and removed if they aren’t needed anymore!

• This bit with the tornado.access logger no longer seems to be necessary:

  web-monitoring-diff/web_monitoring_diff/server/server.py

  Lines 44 to 46 in 0abd10f

  	# Tornado logs any non-success response at ERROR level, which Sentry captures
  	# by default. We don't really want those logs.
  	sentry_sdk.integrations.logging.ignore_logger('tornado.access')

• We should probably enable or have a way to enable tracing! This would be really useful performance telemetry.

• Sentry now has a logs feature, should we still be using breadcrumbs?

  web-monitoring-diff/web_monitoring_diff/server/server.py

  Lines 618 to 623 in 0abd10f

  	sentry_sdk.add_breadcrumb(category='request', data={
  	'url': self.request.full_url(),
  	'method': self.request.method,
  	'headers': headers,
  	})
  	sentry_sdk.add_breadcrumb(category='response', data=response)