Telemetry improvements (#1886)

* Fix typo

* Support multiple telemetry endpoints and verbosity levels

* Bump substrate-telemetry version

* Telemetrify Aura consensus

* Telemetrify Grandpa

* Fix CI version conflicts

* Implement style remarks

* Fix fixture

* Implement style remarks

* Clone only when necessary

* Get rid of Arc for URL

* Handle connection issues better