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

* Tip are never destroyed when change view mode
* unbind methods
* mail: memory leak with unbind methods
* web: memory leak because 'ui-autocomplete' is never destroyed
* web_editor: memory leak for wrong unbind on destroy
* web: memory leak: must remove fileupload handler
* bus: memory leak: correctly debind handlers on window in bus.Bus
* remove handlers on switch buttons and views $buttons
* remove handlers on breadcrumbs
* web: memory leak: correctly debind handlers
* im_odoo_support: memory leak: remove fileupload handler odoo_support

Note: part of this commit was actually authored by aab

When the user visited a view for the second time, the extra actions in the sidebar
were broken.  The reason is that the sidebar code modified in place the
fields_view information.

Note: This was not a problem before, because the field_view_get call was done each
time the view was loaded, but now it is cached.

Avoid duplicating web addon in enterprise by extracting a common basis.
Enterprise features stay in enterprise, but use that common basis.

Mainly:
 - JS refactoring and linting
 - Conversion of .sass into .less split into multiple files
 - Templates cleaning and DOM simplification
 - Re-generation of web.pot, and update of .po files

On webclient, on 'Attachment(s)' dropdown (form view) when clicking on an attachment to download it, a request is sent to /web/content/ with a param 't' containing the current date. This param wasn't used neither before the new controller, but the old one accept additional kwargs. The new controller crashes, and since the t parameter is not used, removing it seems better.

oe_form_binary_form -> o_form_binary_form
oe_form_binary_file -> o_form_input_file

Required for new design compatibility (classnames accessed in addon mail)