[enrichment/trace] Use parsed stacktrace for calculating error grouping key

[lahsivjar]

From: #99 (comment)

Parse the stacktrace (removing any line number, exception message, etc) and use the hashed as a parameter to calculate the grouping key.

[gregkalapos]

From weekly sync:

we can use this information to also fill error.culprit. That field is currently not present in OTel data, but often used on the UI.

(Of course it's ok to move this into a separate issue if needed)