[IMP] website_crm_partner_assign: use geoip to display partners in the visitor's country.

Also added a breadcrumb in partners navigation; when going on the partner view
a link to come back to the list view has been added and takes into account
selected grade and country.
[FIX] website_forum: when sending emails about forum post, use the public url instead of the private
[FIX] crm: do not overwrite the value of no_force_assignation if already set in the context