This commit introduce a full redesign of all JS views.  We started
basically from scratch.  The goal was to unify all the various views
under a common framework, to make them testable, to make then usable in
different conditions (in studio, or in the frontend), and to make our
lives easier.

Some important points are:
- we introduced new coding guidelines (camelCase, 80 chars width, ...)
- we have a brand new testing framework (still QUnit based)
- kanban view moved to the web addon
- calendar view (formerly web_calender) moved to web as well
- the tree view was removed
- all new code should be documented

We hope that this code is the start of a new era for the Odoo web
client, we want to have a high quality codebase, well documented, well
tested, well designed.

Work done by the framework team: mostly aab, ged, chm, dmo, qsm

issue: xml template are not translated anymore

rev d56b35e2 moved qweb code inside the `qweb.js` file and also changed
the behavior with the introduction of a `QWeb` factory returning instances
of qweb rendering engine. However, we have to set on the rendering engine
instance a `preprocess_node` function that will translate the qweb
templates.

The solution for this issue (also introduced with rev d56b35e2) was
to set this function on the prototype of the QWeb factory, and it was
obviously not enough as it has to be attached to the rendering engine
instance.

In order to benefit from the fact that the `preprocess_node` function
is attached to the prototype of the QWeb factory, we could attach it to
the rendering engine instance with something like
`qweb.preprocessed_node = this.preprocessed_node`, however i find that
conceptually attaching a translate function to a factory does not make
sense, si i simply made `preprocess_node` a free function and i set it
on rendering engine instance.

In a previous refactor, qweb configuration was simplified.  However, I
missed the fact that session.js sneakily configure the qweb instance
after the fact. As a result, the kanban view did not have the _s key in
its custom qweb instance default dict.  This commit allow the qweb class
constructor to add default keys to the instance.

Now, kanban view can add _s, and everything is good.

this js module centralizes all odoo initialization