Can you use the default resource pack as a template?

Yes this is possible.

  1. Navigate to your .minecraft folder (%appdata%/.minecraft/ on Windows usually)
  2. Open versions folder
  3. Open the folder for the version you would like to create a resource pack for
  4. Open the .jar file with an archiving software such as WinRAR (right click, Open with WinRAR)
  5. Navigate inside the assets folder and extract the minecraft folder
  6. That folder is now your resource pack template! Rename the folder to whatever you would like to name your resource pack and copy it into the Resource packs folder. You can now edit it as you wish!

Hope I helped. If you need any more details or would like me to create a template for you to use (I guarantee it will be safe!) just comment.