Rule mining: Configure threshold for percentage of exceptions

Currently we supported a threshold of 20% of maximum exceptions on entitlements. This means that within the person scope of the condition at maximum of 20% could be seen as exception and not having the entitlement to be visible as report entry. We made this configurable between 20% and 0%. This means we are more flexibel within the report because a group exclude could now be included as an report entry because the whole group is smaller than 20% of the organization especially higher level scopes like two division where one is really big an the other is really small. Another big advantage is that we can set this percentage on 0% which makes it much easier to create rules for a first setup.