Proposal to redesign the memberOf plugin (v2)

Let us start with the following setup:

dn: name=Group A, cn=Groups, cn=default, cn=sysdb
objectClass: group
member: name=Group D, cn=Groups, cn=default, cn=sysdb
member: name=User 1, cn=Users, cn=default, cn=sysdb
member: name=User 2, cn=Users, cn=default, cn=sysdb
member: name=User 3, cn=Users, cn=default, cn=sysdb
member: name=User 4, cn=Users, cn=default, cn=sysdb
member: name=User 5, cn=Users, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb

dn: name=Group B, cn=Groups, cn=default, cn=sysdb
objectClass: group
member: name=Group D, cn=Groups, cn=default, cn=sysdb
member: name=User 1, cn=Users, cn=default, cn=sysdb
member: name=User 2, cn=Users, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb

dn: name=Group C, cn=Groups, cn=default, cn=sysdb
objectClass: group
member: name=Group A, cn=Groups, cn=default, cn=sysdb
member: name=Group B, cn=Groups, cn=default, cn=sysdb
member: name=Group F, cn=Groups, cn=default, cn=sysdb
member: name=User 3, cn=Users, cn=default, cn=sysdb

dn: name=Group D, cn=Groups, cn=default, cn=sysdb
objectClass: group
member: name=User 4, cn=Users, cn=default, cn=sysdb
memberOf: name=Group A, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group B, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb

dn: name=Group E, cn=Groups, cn=default, cn=sysdb
objectClass: group
member: name=User 5, cn=Users, cn=default, cn=sysdb
memberOf: name=Group B, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group F, cn=Groups, cn=default, cn=sysdb

dn: name=Group F, cn=Groups, cn=default, cn=sysdb
objectClass: group
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb


dn: name=User 1, cn=Users, cn=default, cn=sysdb
objectClass: user
memberOf: name=Group A, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group B, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb

dn: name=User 2, cn=Users, cn=default, cn=sysdb
objectClass: user
memberOf: name=Group A, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group B, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb

dn: name=User 3, cn=Users, cn=default, cn=sysdb
objectClass: user
memberOf: name=Group A, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb

dn: name=User 4, cn=Users, cn=default, cn=sysdb
objectClass: user
memberOf: name=Group A, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group B, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group D, cn=Groups, cn=default, cn=sysdb

dn: name=User 5, cn=Users, cn=default, cn=sysdb
objectClass: user
memberOf: name=Group A, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group B, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group C, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group E, cn=Groups, cn=default, cn=sysdb
memberOf: name=Group F, cn=Groups, cn=default, cn=sysdb