feat: move all alert ingestion logic to engines/ folder

[shahargl]

** Current architecture/design **

Currently, there is a lot of logic around alerts including:

1. deduplication (alert_deduplicator/)
2. enrichment (enrich_alert in db.py)
3. mapping and extraction (EnrichBl under bl)
4. search engine (search_alerts/)
5. rules engine (rule_engine/)

** Why is this change needed? **

1. It is hard to understand all the changes/logic that touch alerts
2. No clear guidelines how to do things (e.g. some cases use direct access to db, some have wrapper around it)

** Expected behavior **

1. All logic sits under engine/ folder.
2. No direct operations on alerts directly on db

[talboren]

@shahargl is this still relevant?