slapos_accounting: Fixup Constraints to not make Reversal Transactions inconsistent

master/bt5/slapos_accounting/SkinTemplateItem/portal_skins/slapos_accounting/Base_testSlapOSValidTradeCondition.py

 root_trade_condition_list = ["sale_trade_condition_module/slapos_aggregated_trade_condition",
-                             "sale_trade_condition_module/slapos_aggregated_subscription_trade_condition"]
+                             "sale_trade_condition_module/slapos_aggregated_subscription_trade_condition",
+                             
+                             # Valid trade condition for payments
+                             "sale_trade_condition_module/slapos_manual_accounting_trade_condition"]
 
 if context.getSpecialise() in root_trade_condition_list:
   return True

master/bt5/slapos_accounting/SkinTemplateItem/portal_skins/slapos_accounting/SaleInvoiceTransaction_isTotalPriceEqualAccounting.py

 invoice = context
 
 total_price = invoice.getTotalPrice()
+if invoice.getTotalPrice() < 0:
+  # For a negative total is from the Reversal transactions
+  total_price *= -1 
+
 accounting_price = invoice.AccountingTransaction_getTotalCredit()
 precision = invoice.getPriceCurrencyValue().getQuantityPrecision()
 return round(total_price, precision) == round(accounting_price, precision)

master/bt5/slapos_accounting/SkinTemplateItem/portal_skins/slapos_accounting/SaleInvoiceTransaction_isTradeModelCorrect.py

 specialise = context.getSpecialiseValue(portal_type='Sale Trade Condition')
+if specialise.getSpecialiseValue() is None:
+  # The trade model don't applies if the Trade Condition isn't attached to 
+  # A business process
+  return True
+
 amount_list = specialise.getAggregatedAmountList(context)
 if len(amount_list) < 1:
   return False