[IMP] base: Add support for private addresses

This is a backport of commit https://github.com/odoo/odoo/commit/2f15a5fa647d55df36c9019df467802a3aa9b4e3

Purpose
=======

Add the possibility to create private addresses, only accessible for a subset
of users.

Specification
=============

- Add a new 'Private' partner type
- Add a res.groups in base 'Access to Private Addresses'
- Add ir.rules for the following behavior:
    - Every employees/internal users can read non-private addresses
    - Only users in group_private_addresses can access private addresses
- Add in base a simplified form view for private addresses

The following points won't be backported:
- A HR Officer is automatically granted in group_private_addresses
- Use the simplified form view to open the address_home_id form on employees
That's because it requires to update 'base' to make it work. If a user only
update 'hr', this will break his instance while 'base' isn't updated.

But these modifications can be applied manually quite easily.