tmf: Bug492895: Avoid unnecessary refreshes during import operation

tmf: Bug492895: Avoid unnecessary refreshes during import operation

This is achieved by using the TmfWorkspaceModifyOperation which
defers the refresh to the end of the operation. Also, setting a trace
type won't refresh the project explorer anymore. The refresh will
be handled at the end of the operation.

Change-Id: I302d54d18b8640b833fc964d5fe74eca06057c15
Signed-off-by: Bernd Hufmann <Bernd.Hufmann@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/71908
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>