[IMP] l10n_*: add demo company

Task 2198388

When testing and demoing localization, it can but cumbersome to create a
Company with the right credentials and install the chart of account on
it.
This commit aims to shorten the process. The first version only contains
a valid vat (or similar) number, but we should add fields specific to
localization in the future so that we have a working environment as soon
as we install the localization.
change manifest

closes odoo/odoo#48102

Signed-off-by: Josse Colpaert <jco@openerp.com>