This adds support for optional policies to the user acceptance reports.
Distinguished are "Pending" acceptances (we did not hear yet) from
"Declined" (user did not agree). The status workflow updated to support
new transitions: pending -> declined and declined -> accepted.
The policies can be revoked by clicking the "Agreed [on behalf]" ticks.
A message has been added also to explain users they must contact to
the DPO if they want to withdraw their consent to policies.