[REF] Contract Sale Invoicing: split from analytic account

[REF] Contract Sale Invoicing: update translations

[IMP] - Assert that the predecessor is available for new link at uncancel

[RMV] - remove usless changes

[RMV] - Remove usless field recurring_invoices

after the total isolation between contract model and account analytic one.
recurring_invoices which was used to mark analytic account as contract became usless

[IMP] - P3 syntax

[IMP] - use @openupgrade.migrate() and openupgrade.logged_query

[IMP] - drop transient table in migration script

contract/__manifest__.py

@@ -13,10 +13,9 @@
     'category': 'Contract Management',
     'license': 'AGPL-3',
     'author': "OpenERP SA, "
-    "Tecnativa, "
-    "LasLabs, "
-    "ACSONE SA/NV, "
-    "Odoo Community Association (OCA)",
+              "Tecnativa, "
+              "LasLabs, "
+              "Odoo Community Association (OCA)",
     'website': 'https://github.com/oca/contract',
     'depends': ['base', 'account', 'product'],
     "external_dependencies": {"python": ["dateutil"]},