Recover from chat room duplication in the database.

When starting the core, make sure that there is not other chatroom
already retrieved that has the same conference id when the gr parameter
is ignored on the peer and local address. If so, then keep the one that
has the oldest creation time and replace it by the value stored in the
other.
All events linked to the to-be-deleted chat room generated before chat room creation time are moved as
they now belong to the kept chat room. The other events are simply
deleted because they are linked ot both chatrooms.

Split suite "Local conference tester (Chat)" into "Local conference tester (Chat Basic)" and "Local conference tester (Chat Advanced)"