HydraulicStructure: Fix KP db type.

src/Model/HydraulicStructures/HydraulicStructures.py

@@ -61,8 +61,8 @@ class HydraulicStructure(SQLSubModel):
             id INTEGER NOT NULL PRIMARY KEY,
             name TEXT NOT NULL,
             enabled BOOLEAN NOT NULL,
-            input_kp INTEGER,
-            output_kp INTEGER,
+            input_kp REAL NOT NULL,
+            output_kp REAL NOT NULL,
             input_reach INTEGER,
             output_reach INTEGER,
             FOREIGN KEY(input_reach) REFERENCES river_reach(id),