Update Go module path from Gitea to GitHub

Change module path from:
  gitea.engen.priv.no/klauvsteinen/unifi-network-operator
To:
  github.com/vegardengen/unifi-network-operator

This fixes the module path mismatch error in GitHub Actions.

Changes:
- Updated go.mod module declaration
- Updated all import statements in Go files
- Updated kustomization and ko config files
- Ran go mod tidy to update dependencies

This is required for the project to build correctly on GitHub.

ko.yaml

@@ -2,6 +2,6 @@ defaultBaseImage: cgr.dev/chainguard/static:latest
 
 labels:
   org.opencontainers.image.authors: Vegard Engen <vegard@engen.priv.no>
-  org.opencontainers.image.source: https://gitea.engen.priv.no/klauvsteinen/unifi-network-operator
+  org.opencontainers.image.source: https://github.com/vegardengen/unifi-network-operator
   org.opencontainers.image.vendor: Klauvsteinen
   dev.chainguard.package.main: ""