[dashboard] Add branding config (#1460)

Signed-off-by: Andrei Kvapil <kvapss@gmail.com>

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## What this PR does


### Release note

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```release-note
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## Summary by CodeRabbit

- New Features
- Introduces dynamic branding support. Tenant name, footer text, title,
logo text, logo SVG, and icon SVG can now be customized via cluster
configuration.
- Branding values are pulled automatically at runtime, enabling
per-tenant look and feel without app redeploys.
- Ensures consistent, centralized control over visual identity across
the dashboard.

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packages/system/dashboard/Makefile

@@ -67,4 +67,4 @@ image-token-proxy:
 	rm -f images/token-proxy.json
 
 update-tenant-text:
-	yq -i '.data.TENANT_TEXT = "$(TAG)"' ./templates/configmap.yaml
+	sed -i 's|\($$tenantText := "\)[^"]\+|\1$(TAG)|' templates/configmap.yaml