Improve code completion and navigation for field inheritance locator

[trinhanhngoc]

https://www.odoo.com/documentation/15.0/developer/reference/backend/views.html#inheritance-specs

-> Code completion should also suggest field tag.

-> Code completion should also suggest name attribute.

-> Code completion should suggest only existing fields in the inherited view.

-> Field reference should be resolved to the correct location (model awareness). https://github.com/odoo-ide/pycharm-odoo/issues/242