Dashboard: promote features in the right bar (#11287)

* Dashboard: promote features in the right bar

Small logic to decide which feature to promote.
This is pretty simple for now, but it shows the pattern we are thinking about.

Required by readthedocs/ext-theme#103

* Improve logic from feedback

* Move partials to a better place

* Updates from feedback

readthedocs/projects/views/private.py

@@ -40,6 +40,7 @@
 from readthedocs.core.history import UpdateChangeReasonPostView
 from readthedocs.core.mixins import ListViewWithForm, PrivateViewMixin
 from readthedocs.core.notifications import MESSAGE_EMAIL_VALIDATION_PENDING
+from readthedocs.core.permissions import AdminPermission
 from readthedocs.integrations.models import HttpExchange, Integration
 from readthedocs.invitations.models import Invitation
 from readthedocs.notifications.models import Notification
@@ -113,6 +114,25 @@ def get_context_data(self, **kwargs):
             # Alternatively, dynamically override super()-derived `project_list` context_data
             # context[self.get_context_object_name(filter.qs)] = filter.qs
 
+            projects = AdminPermission.projects(user=self.request.user, admin=True)
+            n_projects = projects.count()
+            if n_projects < 3 and (timezone.now() - projects.first().pub_date).days < 7:
+                template_name = "example-projects.html"
+            elif (
+                n_projects
+                and not projects.filter(external_builds_enabled=True).exists()
+            ):
+                template_name = "pull-request-previews.html"
+            elif (
+                n_projects
+                and not projects.filter(addons__analytics_enabled=True).exists()
+            ):
+                template_name = "traffic-analytics.html"
+            else:
+                context["promotion"] = "security-logs.html"
+
+            context["promotion"] = f"projects/partials/dashboard/{template_name}"
+
         return context
 
     def validate_primary_email(self, user):