Option to set self-registered users in pending state

A new option is added to the self registration configuration to define the user status for self-registered users. The options are: 

• Active
• Pending
• Pending if one of the following user properties matches:

In the last option it is possible to configure up to 5 user properties. At least one must be selected. 

The idea is to set a user into pending state based on self declared properties. This could be the domain of a mail address or a checkbox that has been checked. 

In case of option 2 and 3 (pending), an email address can be added (multiple mail addresses separated by comma) who should be notified when new users are set into pending state. In this case, an email is sent to this mail addresses with the link to the user profile. They can then activate the user or delete the account.