slapos_erp5: production users can create invitation token

slapos_erp5: do not allow creating Contract Invitation Token anymore

slapos_erp5: invitation token roles

slapos_erp5: trigger invitation token local role generation

slapos_erp5: is an Invitation Token a ticket?

slapos_erp5: test invitation token roles

slapos_erp5: roles for Assignment Request

slapos_subscription_request: WIP: stop using discount resource, and reduce the quantity of the consumed software product / service