Allow TODO to be placed on GameObject or Prefabs

[DarkRewar]

Let the possibility for users to add todos directly on GameObject/Prefab.

The entry will be added to the TODO List, on the same level than code todos.

How this could work?

Two options:

• making a component that could be binded to GameObject or Prefab and will link to an entry in todo list
• creating a todo that can reference any Unity Object and opens it (or reveal in finder) when it is clicked