make separate binaries: egui_cmd and egui

 - src/bin - source files which are needed to build egui
   but in CMakeLists for this dir target will be build with -DCMD_MODE
   define. Binary: "egui_cmd" will be build.

 - src/bin/egui_gui - CMakeLists which takes sources from /src/bin
   and builds without CMD_MODE definition.
   Binary "egui" will be build and copied into /build/src/bin.

   Need to move all gui files ino src/bin/egui_gui and generate
   gui_layout.