Add import netclass color menu items to PCB appearance widget

Fixes https://gitlab.com/kicad/code/kicad/-/issues/16908

ADDED: Context menu item in PCB appearances widget to import netclass
color from schematic.
ADDED: Context menu item to reset PCB netclass color (replicating
same menu item from Nets inspector)

include/project/net_settings.h

@@ -62,6 +62,14 @@ public:
 public:
     std::shared_ptr<NETCLASS> GetEffectiveNetClass( const wxString& aNetName ) const;
 
+    /**
+     * Get a NETCLASS object from a given Netclass name string
+     * 
+     * @param aNetClassName the Netclass name to resolve
+     * @return shared pointer to the requested NETCLASS object, or the default NETCLASS
+    */
+    std::shared_ptr<NETCLASS> GetNetClassByName( const wxString& aNetName ) const;
+
     /**
      * Parse a bus vector (e.g. A[7..0]) into name, begin, and end.
      *