added support for user-specific DCP and input ICC profiles dirs

Look for direcories dcpprofiles/ and iccprofiles/input/ under Options::rtdir
(typically something like $HOME/.config/RawTherapee)

rtengine/dcp.h

@@ -166,7 +166,7 @@ private:
     DCPStore() = default;
 
     mutable MyMutex mutex;
-    Glib::ustring profileDir;
+    std::vector<Glib::ustring> profileDir;
 
     // these contain standard profiles from RT. keys are all in uppercase, file path is value
     std::map<Glib::ustring, Glib::ustring> file_std_profiles;