Move fis widgets SQL into scalar functions

Add fis_wdg_* table functions for dashboard widgets and wire them into
FuchsDatabase.sqlproj; update the invoice list procs accordingly.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fuchs_Database/dbo/Functions/fis_wdg_requests_today.sql

@@ -0,0 +1,20 @@
+-- =============================================
+-- Description:	Dashboard widget 'wdg_requests_today' (Aufträge terminiert für heute).
+--              Called from [dbo].[fis_widgets].[sql] as: SELECT * FROM [dbo].[fis_wdg_requests_today]()
+-- =============================================
+CREATE FUNCTION [dbo].[fis_wdg_requests_today]()
+RETURNS TABLE
+AS
+RETURN
+(
+    WITH osrq AS (
+        SELECT s.[id], s.[name], s.[externalid], s.[customerId]
+             , [last_appointment] = MAX(CAST(a.[startdatetime] as date)), [#a] = COUNT(*)
+          FROM [dbo].[mfr__servicerequests] AS s
+               JOIN [dbo].[mfr__appointments] AS a ON s.[id] = a.[ServiceRequestId]
+         WHERE s.[state] IN ('Scheduled', 'Released', 'InProgress')
+         GROUP BY s.[id], s.[name], s.[externalid], s.[customerId])
+    SELECT [Nummer] = [externalid], [Auftrag] = [name], [Kunde] = [dbo].[fds__getCompanyName]([customerId])
+      FROM osrq
+     WHERE [last_appointment] = CAST(GETDATE() as date)
+);