Themes image would not be shown correctly in the theme selection if the `website` module was installed in CLI. Indeed, the code supposed to load the theme images was done in the kanban view during theme selection after installing module through apps screen. Now, this code is encapsulated and called in post_init hook of website. This was also needed for an improvement on `test_themes` module, see https://github.com/odoo/design-themes/pull/195. closes odoo/odoo#42206 Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>