BECDock - rpc CLI

Make a CLI interface to replace current BECFigure in BECIPythonClient based on pyqtgraph.dockarea.DockArea (see https://pyqtgraph.readthedocs.io/en/latest/api_reference/dockarea.html)

This will allow us to add any type of widgets to CLI GUI which is launched with BECClient.