Enable member creation functionality: implement MemberAddView, create MemberForm, update routes, templates, and add supporting styles.

templates/backend/partials/messages.html

@@ -0,0 +1,29 @@
+{% if messages %}
+    <div id="messages" class="flex flex-col p-2 m-4 -mt-4 gap-y-2" {% if request.htmx %} hx-swap-oob="true"{% endif %}>
+        {% for message in messages %}
+            {% if message.level == DEFAULT_MESSAGE_LEVELS.SUCCESS %}
+                <div role="alert" class="alert alert-success">
+                    <i class="text-lg fa-solid fa-check"></i>
+                    <span>{{ message|safe }}</span>
+                </div>
+            {% elif message.level == DEFAULT_MESSAGE_LEVELS.WARNING %}
+                <div role="alert" class="alert alert-warning">
+                    <i class="text-lg fa-solid fa-ban"></i>
+                    <span>{{ message|safe }}</span>
+                </div>
+            {% elif message.level == DEFAULT_MESSAGE_LEVELS.ERROR %}
+                <div role="alert" class="alert alert-error">
+                    <i class="text-lg fa-solid fa-exclamation"></i>
+                    <span>{{ message|safe }}</span>
+                </div>
+            {% else %}
+                <div role="alert" class="alert alert-info">
+                    <i class="text-lg fa-solid fa-info"></i>
+                    <span>{{ message|safe }}</span>
+                </div>
+            {% endif %}
+        {% endfor %}
+    </div>
+{% else %}
+    <div id="messages"{% if request.htmx %} hx-swap-oob="true"{% endif %}></div>
+{% endif %}