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>