[IMP] website: move facebook page snippet options in left panel

Before this commit, the configuration of the facebook page snippet was
done in a modal window. In an effort to streamline and unify snippet
options, the configuration has been moved into the left panel.

task-2146928

closes odoo/odoo#41104

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>