Refactor risk management

Signed-off-by: gearnode <bryan@frimin.fr>

pkg/coredata/migrations/20250411T233300Z.sql

@@ -0,0 +1,7 @@
+CREATE TABLE risks_policies (
+    risk_id TEXT NOT NULL REFERENCES risks(id),
+    policy_id TEXT NOT NULL REFERENCES policies(id),
+    tenant_id TEXT NOT NULL,
+    created_at timestamp NOT NULL,
+    PRIMARY KEY (risk_id, policy_id)
+);