[IMP] packaging: update windows packaging

Up to Odoo 13.0, the windows setup is 32 bits and embeds an old
postgresql 9.5 32 bits version too.

With this commit, the postgresql server is no longer embedded in the
resulting setup file. Instead, if the user choose to install the
postgresql server, the 12.4 version is downloaded from the official site
(version 10.14 in the case of a 32 bits windows).

Also, the Python target achitecture is choosen based on the Windows
system on which Odoo is installed.

This imply changes on the KVM images used to build the installer:

    - The Windows system on the KVM as to be 64 bits.
    - A 32 bits WinPython version must be in `c:/odoobuild/WinPy32`
    - A 64 bits WinPyhton version must be in `c:/odoobuild/WinPy64`

A little bit of cleaning also comes with this commit to get rid of the
old `openerp` references.

closes odoo/odoo#57155

Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>