ProjectExplorer: Use Core::Id as RunMode "enum values"

This provides a way for third-party plugins to implement run
modes without the need to add a value to the central enum or
using manual workarounds like RunMode(*(int*)&someUniqueObject).

Instead of centrally defined enum values this uses Core::Id that could
be defined anywhere.

Change-Id: Ic350e3d8dbb8042c61b2d4ffec993ca151f53099
Reviewed-by: Daniel Teske <daniel.teske@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/plugins/valgrind/callgrindtool.h

@@ -41,6 +41,8 @@ const char CallgrindLocalActionId[] = "Callgrind.Local";
 const char CallgrindRemoteActionId[] = "Callgrind.Remote";
 
 class ValgrindRunControl;
+const char CALLGRIND_RUN_MODE[] = "CallgrindTool.CallgrindRunMode";
+
 class CallgrindToolPrivate;
 
 class CallgrindTool : public QObject