Reformat the database comment and handle character limit

Previous comment format:

"generated by auto prescaler 
Compared to key 2051 
(AUTO_Physics_pp_run3_v1) 
prescaled items: L1_J12_EMPTY (cut 14913082->16771848), "

New comment format:

"Original key 2051 
prescaled items: L1_J12_EMPTY, "

If the comment exceeds 200 character limit (Trigger DB), the comment will be cut, and "..." will be added in the end.

Tagging @mark