Add mitigation with task and mapping import

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

pkg/coredata/migrations/20250401T173800Z.sql

@@ -0,0 +1,11 @@
+ALTER TABLE controls_mitigations
+    ADD CONSTRAINT fk_controls_mitigations_control_id
+    FOREIGN KEY (control_id)
+    REFERENCES controls(id)
+    ON DELETE CASCADE;
+
+ALTER TABLE controls_mitigations
+    ADD CONSTRAINT fk_controls_mitigations_mitigation_id
+    FOREIGN KEY (mitigation_id)
+    REFERENCES mitigations(id)
+    ON DELETE CASCADE;