[IMP] base_import, web: add view switcher and h 'Import' button in mobile

As there are a few chance that someone will import something on a mobile view.
So, we hide the button 'Import' in a mobile view.

For mobile view, we added a view switcher button and it'll display a list of
views buttons. Also set active view's icon as its icon.

Related to Task: 1857696
Co-authored-by: Mohammed Shekha <msh@openerp.com>