[ADD] web_unsplash: Find free high-resolution images from Unsplash

This commit:
1. Adds settings to install the new `web_unsplash` enterprise module.
   See counterpart commit on enterprise for details.
2. Export `ImageWidget` and `update_control_panel` to be able to override them.
3. Add the unsplash access key rights to website designer. (see related OE
   commit)

task-35060
Closes #25825, closes #25637

addons/base_setup/models/res_config_settings.py

@@ -30,6 +30,7 @@ class ResConfigSettings(models.TransientModel):
     module_inter_company_rules = fields.Boolean("Manage Inter Company")
     module_pad = fields.Boolean("Collaborative Pads")
     module_voip = fields.Boolean("Asterisk (VoIP)")
+    module_web_unsplash = fields.Boolean("Unsplash Image Library")
     company_share_partner = fields.Boolean(string='Share partners to all companies',
         help="Share your partners to all companies defined in your instance.\n"
              " * Checked : Partners are visible for every companies, even if a company is defined on the partner.\n"

addons/base_setup/views/res_config_settings_views.xml

@@ -233,6 +233,17 @@
                                     </div>
                                 </div>
                             </div>
+                            <div class="col-xs-12 col-md-6 o_setting_box">
+                                <div class="o_setting_left_pane">
+                                    <field name="module_web_unsplash" widget="upgrade_boolean"/>
+                                </div>
+                                <div class="o_setting_right_pane" id="web_unsplash_settings">
+                                    <label for="module_web_unsplash"/>
+                                    <div class="text-muted">
+                                        Find free high-resolution images from Unsplash
+                                    </div>
+                                </div>
+                            </div>
                         </div>
                     </div>
                 </xpath>