At most until everything has been implemented.

* Implement Extension Component.
  * Complete ExtensionComponent view.
  * Add component_interaction_workflow to reset erp5.component when modifying an Extension Component.

For now this is a global reset, meaning that everytime a component is changed,
all the component are reset, which is terrible from a performance point of
view.

Return a safe html selenium test code (which always fails) to indicate a problem when download a test. This will prevent Zelenium get Stalled during the launch.

Follow up commit e0855913

Code cleaned up from not needed variables.

Key in _local_properties does not have to match key in property sheets. So
just blindly try to migrate everything from _local_properties and *only* from
there.