Upsert rather than clear collections every time we update the db

[vzcodes]

Note

Low Risk
Low risk: only changes initialization scripts to avoid dropping collections by default and adds an explicit --reset option; impact is limited to how/when rating list data is wiped during runs.

Overview
Rating list initialization now runs in incremental update mode by default and only drops/recreates DB collections when explicitly requested.

Adds a --reset flag to both init_ratings.py and initialize_rating_lists.sh, updates logging/usage output accordingly, and passes the flag through the shell script into the generated Python runner.

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