Removed Freecad and colors from the classic theme.

Otherwise if you keep naming the same you'll get "Freecad Dark colors" and "Freecad light colors" now it is:
Dark
Light
Classic

src/Gui/PreferencePacks/CMakeLists.txt

@@ -4,7 +4,7 @@ SET(PreferencePacks_Files
 )
 
 SET(PreferencePacks_Directories
-"FreeCAD Classic Colors"
+"Classic"
 "Dark"
 "Light"
 )

src/Gui/PreferencePacks/package.xml

@@ -9,7 +9,7 @@
 
   <content>
     <preferencepack>
-      <name>Classic Colors</name>
+      <name>Classic</name>
       <description>FreeCAD default colors for core app and included Mods.</description>
       <version>1.0.0</version>
       <tag>built-in</tag>