Use the proper index from the proper model to when adding sg's

The row we get from the servergrouplist index is what the
source model uses. Due to filtering this might not be the same
row for the filtermodel.
Send proper signals when server groups are added / removed

Also added TODO's for where we need to send signals if child
rows were added or removed.
Properly update the view when the server group model has changed

Now the signals are emitted for all changes including child
items.

There is a separate signal for the parent and the children
because dataChanged can't handle ranges that have different
parents.
Add back port and ssl status information from old server list

Adding back old functionality using the same format as the old
server list code.