feat: manage branding profiles in the NetBox UI

New BrandingProfile model (migration 0001) with logo upload, color
pickers, font, Word template upload, table style and extra CSS, plus
list/edit/delete views, an HTML preview and a menu entry with add
button. Access is controlled via the model's Django permissions.

Profiles from the database are offered first in the export form (the
default profile preselected); profiles from PLUGINS_CONFIG still work.

Bump version to 0.2.0 - requires "manage.py migrate".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

netbox_customer_export/__init__.py

@@ -5,7 +5,7 @@ class CustomerExportConfig(PluginConfig):
     name = "netbox_customer_export"
     verbose_name = "Kunden-Export"
     description = "Kundendokumentation als PDF oder Word exportieren"
-    version = "0.1.1"
+    version = "0.2.0"
     author = "Claude"
     base_url = "customer-export"
     min_version = "4.6.8"