Use a hook to implement the shift-click shortcut to keyboard prefs...

This frees EIGHTEEN files from the big strongly connected component!!

They are:

Dependencies
Export
ExportCL
ExportFFmpeg
ExportFFmpegDialogs
ExportFLAC
EportMP2
ExportMP3
ExportOGG
ExportPCM
ExtImportPrefs
Import
ImportRaw
KeyConfigPrefs
KeyView
LibraryPrefs
PrefsDialog
SpectrumPrefs

... and that includes all of the remaining *Prefs files.

It does still leave the nine Export* files in a smaller s.c.c, which could be
broken with a registration system, as was done for import at commit e2cf1d9

src/AudacityApp.cpp

@@ -108,6 +108,10 @@ It handles initialization and termination by subclassing wxApp.
 #include "tracks/ui/Scrubbing.h"
 #include "widgets/FileHistory.h"
 
+#ifdef EXPERIMENTAL_EASY_CHANGE_KEY_BINDINGS
+#include "../prefs/KeyConfigPrefs.h"
+#endif
+
 //temporarily commented out till it is added to all projects
 //#include "Profiler.h"
 
@@ -1593,6 +1597,23 @@ bool AudacityApp::OnInit()
    mTimer.SetOwner(this, kAudacityAppTimerID);
    mTimer.Start(200);
 
+#ifdef EXPERIMENTAL_EASY_CHANGE_KEY_BINDINGS
+   CommandManager::SetMenuHook( [](const CommandID &id){
+      if (::wxGetMouseState().ShiftDown()) {
+         // Only want one page of the preferences
+         PrefsDialog::Factories factories;
+         factories.push_back(KeyConfigPrefsFactory( id ));
+         auto pWindow = FindProjectFrame( GetActiveProject() );
+         GlobalPrefsDialog dialog( pWindow, factories );
+         dialog.ShowModal();
+         MenuCreator::RebuildAllMenuBars();
+         return true;
+      }
+      else
+         return false;
+   } );
+#endif
+
    return TRUE;
 }