Implement Command::rawCommand() for edge cases and trigger a proper error

Author: Pierstoval

Command.php

@@ -552,6 +552,32 @@ public function strokeWidth(int $strokeWidth): self
         return $this;
     }
 
+    /**
+     * /!\ Append a raw command to ImageMagick.
+     * Not safe! Use at your own risks!
+     *
+     * @internal
+     */
+    public function rawCommand(string $command, bool $append = false): self
+    {
+        $msg = <<<MSG
+This command is not safe and therefore should not be used, unless you need to use an option that is not supported yet.
+Use at your own risk!
+If you are certain of what you are doing, you can silence this error using the "@" sign on the instruction that executes this method.
+If the option you need is not supported, please open an issue or a pull-request at https://github.com/Orbitale/ImageMagickPHP in order for us to implement the option you need! 😃
+MSG
+;
+        trigger_error($msg, E_USER_DEPRECATED);
+
+        if ($append) {
+            $this->commandToAppend[] = $command;
+        } else {
+            $this->command[] = $command;
+        }
+
+        return $this;
+    }
+
     /* ------------------------------------------ *
      * End of ImageMagick native options.         *
      * Want more? Some options are missing?       *