[IMP] account,account_asset:few usability changes

1. Add an accounting configuration option
   "Assets management & Revenue recognition"

2. Deferred revenue account not set by default in product
    - Create new Deferred Revenue Type
    - Create new product and assign this "Deferred Revenue Type"
      you can see in income account there is nothing set. Actually
      when we select revenue type then in income account system
      have to set "Deferred Revenue Account" which we set on revenue type.
      Otherwise, if we create invoice for this product then system will
      by default take the income account from product category.

3. Change word Depreciation to Revenue :

addons/account/models/res_config.py

@@ -82,6 +82,11 @@ class AccountConfigSettings(models.TransientModel):
         help='Asset management: This allows you to manage the assets owned by a company or a person. '
                  'It keeps track of the depreciation occurred on those assets, and creates account move for those depreciation lines.\n\n'
              '-This installs the module account_asset.')
+    module_account_deferred_revenue = fields.Boolean(string="Revenue Recognition", 
+        help='This allows you to manage the revenue recognition on selling products. '
+             'It keeps track of the installments occurred on those revenue recognitions, '
+             'and creates account moves for those installment lines\n'
+             '-This installs the module account_deferred_revenue.')
     module_account_budget = fields.Boolean(string='Budget management',
         help='This allows accountants to manage analytic and crossovered budgets. '
              'Once the master budgets and the budgets are defined, '

addons/account/views/res_config_view.xml

@@ -121,6 +121,10 @@
                                 <field name="module_account_asset" class="oe_inline"/>
                                 <label for="module_account_asset"/>
                             </div>
+                            <div>
+                                <field name="module_account_deferred_revenue" class="oe_inline" widget="upgrade_boolean"/>
+                                <label for="module_account_deferred_revenue"/>
+                            </div>
                             <div>
                                 <field name="module_account_budget" class="oe_inline"/>
                                 <label for="module_account_budget"/>

addons/account_asset/account_asset_invoice.py

@@ -83,3 +83,8 @@ class ProductTemplate(models.Model):
     _inherit = 'product.template'
     asset_category_id = fields.Many2one('account.asset.category', string='Asset Type', ondelete="restrict")
     deferred_revenue_category_id = fields.Many2one('account.asset.category', string='Deferred Revenue Type', ondelete="restrict")
+
+    @api.onchange('deferred_revenue_category_id')
+    def onchange_revenue_category_id(self):
+        if self.deferred_revenue_category_id:
+            self.property_account_income_id = self.deferred_revenue_category_id.account_depreciation_id.id