loader: Implement ReadProgramId

src/core/loader/ncch.h

@@ -219,6 +219,13 @@ public:
      */
     ResultStatus ReadLogo(std::vector<u8>& buffer) override;
 
+    /**
+     * Get the program id of the application
+     * @param out_program_id Reference to store program id into
+     * @return ResultStatus result of function
+     */
+    ResultStatus ReadProgramId(u64& out_program_id) override;
+
     /**
      * Get the RomFS of the application
      * @param romfs_file Reference to buffer to store data