owl: add devtools

[ged-odoo]

Motivation

A chrome extension to help work with owl would be awesome...

Spec

Create a chrome extension, in the extras folder. It should:

• be a simple Owl application

• be able to see if a component is mounted

• if this is the case, display a tree view of each components:

     App
         NavBar
         Content
             ...
         Footer
  

• Clicking on one of these component would then open on the right side a zone with

  • state
  • props

• Also, this list should be updated whenever the application changes

• Later, the state should be editable

[ged-odoo]

Also, should be easy to switch in dev mode