feat: add navigation context processor and update header template

- Created `navigation` context processor to manage `active` context
- Integrated the processor into Django settings
- Simplified `header.html` by removing `{% with %}` for `active` management

santehray/context_processors.py

@@ -0,0 +1,2 @@
+def navigation(request):
+    return {"active": ""}

santehray/settings.py

@@ -205,6 +205,7 @@ TEMPLATES = [
                 'django.template.context_processors.request',
                 'django.contrib.auth.context_processors.auth',
                 'django.contrib.messages.context_processors.messages',
+                'santehray.context_processors.navigation',
             ],
             'debug': DEBUG
         },