MiscUtil: Optional support for Sentry logging

	* Capture exceptions in register_exception
	* add raven to requirements-extra
	* add CFG_ERRORLIB_SENTRY_URI to config, used to set sentry uri and enable/disable sentry feature.

Signed-off-by: Fredrik Nygård Carlsen <me@frecar.no>
Merge pull request #1 from tind/sentry

MiscUtil: Optional support for Sentry logging
WebSearch: initial support for recjson output

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
errorlib:  support for Sentry logging

* Optionally captures exceptions and sends them to the Sentry logging
  platform, if directed by the new CFG_ERRORLIB_SENTRY_URI configuration
  variable. (closes #1726)

* Adds raven python package to requirements-extra

Signed-off-by: Fredrik Nygård Carlsen <me@frecar.no>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
batchuplader_engine

* Correct bug in batchupload permission checking (closes #1747)