chore: add a .mailmap git file to map author identity variations to unified ones

.mailmap

@@ -0,0 +1,4 @@
+Florian Briand <florian.briand@digital-engine.info> <florian.briand@digital-engine.info>
+theo <theo.lettermann@gmail.com> <t.lettermann@criteo.com>
+kosssi <simon@p4pillon.org> <simonc@linux.com>
+lienjukaisim <julien.misiak@live.com> <154924955+lienjukaisim@users.noreply.github.com>

frontend/components/Avatar.vue

@@ -17,6 +17,6 @@
         if (user.avatar) {
             return user.avatar;
         }
-        return 'https://i.pravatar.cc/150?u=' + user.name;
+        return 'https://avatar.iran.liara.run/username?username=' + user.name;
     };
 </script>

frontend/components/LoginModal.vue

@@ -29,15 +29,15 @@
 
     const users: User[] = [
         { id: 1, name: 'John Doe', avatar: 'https://img.daisyui.com/images/stock/photo-1534528741775-53994a69daeb.webp' },
-        { id: 2, name: 'Jane Doe', avatar: 'https://i.pravatar.cc/150?u=JANEDOE728' },
-        { id: 3, name: 'Michel Moulin' },
-        { id: 4, name: 'Jean Paris' },
-        { id: 5, name: 'Marie Dupont' },
-        { id: 6, name: 'Émilie Fournier' },
-        { id: 7, name: 'Pierre Lefevre' },
-        { id: 8, name: 'Sophie Lemoine' },
-        { id: 9, name: 'Lucie Simon' },
-        { id: 10, name: 'Kevin Boucher' },
+        { id: 2, name: 'Jane Doe', avatar: 'https://avatar.iran.liara.run/public' },
+        { id: 3, name: 'Michel Moulin', avatar: '' },
+        { id: 4, name: 'Jean Paris', avatar: '' },
+        { id: 5, name: 'Marie Dupont', avatar: '' },
+        { id: 6, name: 'Émilie Fournier', avatar: '' },
+        { id: 7, name: 'Pierre Lefevre', avatar: '' },
+        { id: 8, name: 'Sophie Lemoine', avatar: '' },
+        { id: 9, name: 'Lucie Simon', avatar: '' },
+        { id: 10, name: 'Kevin Boucher', avatar: '' },
     ];
 
     const loginModal = useTemplateRef('login_modal');