migrate contacts to enable Group's to be used as group acl's

[bourgeoa]

From mashlib v1.7.3 and NSS v5.6.7 Contacts Group created with contact-pane can be used as group acl.

A manual migration is needed to update the old contacts group.
A migration is only needed if the contacts group do not contain owl:sameAs predicate for a contact with a WebID

The following process must be used to migrate team group (...Contacts/Group/team.ttl :

• in Contacts create a new group : for example : teamBackup
• click on group team
• move each member of team to teamBackup

You now have a Group teamBackup containing all members with the new format.

• delete group team
• create new group team
• then move back all teamBackup members to team
• delete teamBackup

[bourgeoa]

@timbl The above should let you migrate https://solidos.solidcommunity.net/Contacts groups to make them group's acl.
This issue is referenced in the wiki https://github.com/solid/solidcommunity.net/wiki