Add new calculate scripts, add in historical data import

inventory-server/scripts/metrics-new/update_periodic_metrics.sql

@@ -5,7 +5,7 @@
 
 DO $$
 DECLARE
-    _module_name VARCHAR := 'periodic_metrics';
+    _module_name TEXT := 'periodic_metrics';
     _start_time TIMESTAMPTZ := clock_timestamp();
     _last_calc_time TIMESTAMPTZ;
     _abc_basis VARCHAR;
@@ -25,7 +25,7 @@ BEGIN
     WITH LeadTimes AS (
         SELECT
             pid,
-            AVG(GREATEST(1, DATE_PART('day', last_received_date - date))) AS avg_days -- Use GREATEST(1,...) to avoid 0 or negative days
+            AVG(GREATEST(1, (last_received_date::date - date::date))) AS avg_days -- Use GREATEST(1,...) to avoid 0 or negative days
         FROM public.purchase_orders
         WHERE status = 'received' -- Or potentially 'full_received' if using that status
           AND last_received_date IS NOT NULL