Before this commit, when manually unmounting the portal
or one of its parents, the teleported elements were not cleaned
and stayed teleported forever
After this commit, the teleported content is brought back and
unmounted much like any component
closes#531
The component Portal is used to teleport the content
in its slot as a child of an element
somewhere else in the DOM, usually 'body'
It is designed to be transparent and is just here to do the teleportation task
OwlEvents (with method `Component.trigger`) are redirected from
any Component instanciated within the Portal (and therefore teleported
somewhere else) to the place it would have been without teleportation
i.e. they are re-triggered onto the Portal root node
Co-authored-by: Aaron Bohy <aab@odoo.com>
closes#184closes#466
Géry Debongnie