chore: optional DB migrations (#9047)

* chore: optional DB migrations
- add a directory in master/static for "optional migrations" that are not strictly required for deployment but can be useful for added functionality

master/static/optional_migrations/README.md

@@ -0,0 +1,10 @@
+# Optional Database Migrations
+
+This directory contains optional database migrations. While they may be needed to view historical 
+data for some product features, they are time-consuming and not necessary for all use cases.  
+Unlike the migrations in `master/static/migrations/`, these migrations will not run automatically 
+on cluster startup. Instead, they can be run manually with the following command:
+
+```bash
+psql -d $DET_DB_NAME --single-transaction -f $PATH_TO_MIGRATION
+```