Add operators and property owners functionality

- Implemented OperatorListView and OperatorDetailView for managing operators.
- Created corresponding templates for operator listing and detail views.
- Added PropertyOwnerListView and PropertyOwnerDetailView for managing property owners.
- Developed templates for property owner listing and detail views.
- Established relationships between parks and operators, and parks and property owners in the models.
- Created migrations to reflect the new relationships and fields in the database.
- Added admin interfaces for PropertyOwner management.
- Implemented tests for operators and property owners.

manufacturers/admin.py

@@ -0,0 +1,14 @@
+from django.contrib import admin
+from .models import Manufacturer
+
+
+class ManufacturerAdmin(admin.ModelAdmin):
+    list_display = ('name', 'headquarters', 'founded_year', 'rides_count', 'coasters_count', 'created_at', 'updated_at')
+    list_filter = ('founded_year',)
+    search_fields = ('name', 'description', 'headquarters')
+    readonly_fields = ('created_at', 'updated_at', 'rides_count', 'coasters_count')
+    prepopulated_fields = {'slug': ('name',)}
+
+
+# Register the model with admin
+admin.site.register(Manufacturer, ManufacturerAdmin)