* add telemetry to pipelines 2.0
* only collect data if telemetry is on
* reno
* add downsampling
* typing
* manual tests
* pylint
* simplify code
* Update haystack/preview/telemetry/__init__.py
* look for _telemetry_data
* rather index by component type
* black
* mypy
* error handling
* comment
* review feedback & small improvements
* defaultdict
* stray changes
* try-catch
* method instead of attribute
* fixes
* remove print statements
* lint
* invert condition
* always send the first event of the day
* collect specs
* track 2nd and 3rd events too
* send first event and then max 1 event a minute
* rename constant
* black
* add test