- Added new cost type "Customer Purchase Order" to intranet-cost package

- In invoices/view.tcl showing the related customer purchase orders
- Allowing to promote a normal invoice to a timesheet invoice, so that
  the report period is shown

www/invoices/promote-invoice-to-timesheet-invoice.tcl

+# /packages/intranet-timesheet2-invoices/www/invoices/promote-invoice-to-timesheet-invoice.tcl
+#
+# Copyright (c) 2003-2020 ]project-open[
+#
+# All rights reserved. Please check
+# http://www.project-open.com/license/ for details.
+
+
+ad_page_contract {
+    Takes a normal invoice and adds the meta-information to make it
+    a timesheet invoice (which contains service start- and end).
+    @author frank.bergmann@project-open.com
+} {
+    invoice_id:integer
+    { return_url "/intranet-invoices/" }
+}
+
+# ---------------------------------------------------------------
+# Defaults & Security
+# ---------------------------------------------------------------
+
+set current_user_id [auth::require_login]
+set outline_number_enabled_p [im_column_exists im_invoice_items item_outline_number]
+im_invoice_permissions $current_user_id $invoice_id view read write admin
+if {!$write} {
+    ad_return_complaint 1 "<li>[_ intranet-timesheet2-invoices.lt_You_dont_have_suffici]"
+    ad_script_abort
+}
+
+
+
+# ---------------------------------------------------------------
+# Promote
+# ---------------------------------------------------------------
+
+set count [db_string count "select count(*) from im_timesheet_invoices where invoice_id = :invoice_id"]
+if {$count < 1} {
+    db_dml insert "insert into im_timesheet_invoices (
+	invoice_id,
+	invoice_period_start,
+	invoice_period_end
+    ) values (
+	:invoice_id,
+	now() - '1 month'::interval,
+	now()
+    )"
+
+    db_dml up "update acs_objects set object_type = 'im_timesheet_invoice' where object_id = :invoice_id"
+}
+
+# ---------------------------------------------------------------
+# Where do you want to go now?
+# ---------------------------------------------------------------
+
+ad_returnredirect "/intranet-invoices/view?invoice_id=$invoice_id"