Refactor imscope
This MR refactors imscope by introducing changes to the default layout
in the config file imgui.ini. The global settings are moved to a new
menu item. This modified layout is intended as a suggestion subject to
change based on feedback. This MR also adds PDCCH LLR and IQ plots to
the UE scope and set axes to AutoFit by default.
The MR has a screenshot of the new layout.