slapos_accounting: invoice builder: dates are now set on delivery. Do not modify causality if it exists

Previously, we has 1 invoice per simulation tree.
But we want to reduce the number of invoice, without using the "aggregate" builder trick

slapos_accounting: stop checking specialise == getPreferredAggregatedSaleTradeCondition. Check ledger instead

slapos_accounting: keep slapos_legacy_aggregated_subscription_trade_condition_2022 when uninstalling it