fix: add deleted_at to advisory_affected_ranges (CM-1258)

Signed-off-by: Uroš Marolt <uros@marolt.me>

Author: themarolt

backend/src/osspckgs/migrations/V1784567585__advisory_affected_ranges_soft_delete.sql

@@ -0,0 +1,5 @@
+ALTER TABLE advisory_affected_ranges ADD COLUMN IF NOT EXISTS deleted_at TIMESTAMPTZ;
+
+CREATE INDEX IF NOT EXISTS advisory_affected_ranges_live_idx
+   ON advisory_affected_ranges (advisory_package_id)
+   WHERE deleted_at IS NULL;