feat: pluggable profile tabs

Added ProfileTab class to represent a profile tab and made the profile
page render the tabs specified in the hook `profile_tabs`. This allows
plugging in new tabs in the profile page without makeing any changes to
the community module.

community/www/profiles/profile.py

@@ -3,9 +3,20 @@ from community.lms.models import Sketch
 
 def get_context(context):
     context.no_cache = 1
+
     try:
         context.member = frappe.get_doc("User", {"username": frappe.form_dict["username"]})
     except:
         context.template = "www/404.html"
-    else:
-        context.sketches = Sketch.get_recent_sketches(owner=context.member.email)
+        return
+
+    context.profile_tabs = get_profile_tabs(context.member)
+
+def get_profile_tabs(user):
+    """Returns the enabled ProfileTab objects.
+
+    Each ProfileTab is rendered as a tab on the profile page and the
+    they are specified as profile_tabs hook.
+    """
+    tabs = frappe.get_hooks("profile_tabs") or []
+    return [frappe.get_attr(tab)(user) for tab in tabs]