[IMP] base, *: use a many2one for the company report layout

Before this rev. one could set the report layout on the company using a
hardcoded list (background, clean, standard, etc.). Other modules (typically
accounting modules) could add options in this list. The used template was built
on the layout key.

Now, the layout is a many2one field to a newly created model `report.layout`,
which is linked to a view with the layout architecture.

This gives more control to customize reports and create a new layout (without
creating a python module that extend the layout selection).

addons/web/static/tests/fields/basic_fields_tests.js

@@ -40,8 +40,6 @@ QUnit.module('basic_fields', {
                     selection: {string: "Selection", type: "selection", searchable:true,
                         selection: [['normal', 'Normal'],['blocked', 'Blocked'],['done', 'Done']]},
                     document: {string: "Binary", type: "binary"},
-                    image_selection: {string: "Image Selection", type: "selection", searchable:true,
-                        selection: [['background', 'Background'],['boxed', 'Boxed'],['clean', 'Clean'],['standard', 'Standard']]},
                 },
                 records: [{
                     id: 1,
@@ -4828,45 +4826,6 @@ QUnit.module('basic_fields', {
 
         form.destroy();
     });
-
-    QUnit.module('FieldImageSelection');
-
-    QUnit.test('image selection widget in form view', function (assert) {
-        assert.expect(3);
-
-        var nodeOptions = {
-            background: {
-                image_link: '/base/static/img/preview_background.png',
-                preview_link: '/base/static/pdf/preview_background.pdf',
-            },
-            boxed: {
-                image_link: '/base/static/img/preview_boxed.png',
-                preview_link: '/base/static/pdf/preview_boxed.pdf',
-            },
-        };
-        var form = createView({
-            View: FormView,
-            model: 'partner',
-            data: this.data,
-            arch: '<form>' +
-                    '<field name="image_selection" widget="image_selection"' +
-                    ' options=\'' + JSON.stringify(nodeOptions) + '\'/> '+
-                  '</form>',
-            res_id: 2,
-        });
-
-        assert.strictEqual(form.$('.img.img-fluid').length, 2,
-            "Two images should be rendered");
-        assert.strictEqual(form.$('.img.btn-info').length, 0,
-            "No image should be selected");
-
-        // select first image
-        form.$(".img.img-fluid:first").click();
-        assert.ok(form.$(".img.img-fluid:first").hasClass('btn-info'),
-            "First image should be selected");
-
-        form.destroy();
-    });
 });
 });
 });