Create test setup for upstream DNS providers

[abaguas]

During the community meeting on the 30.11.2024 we discussed how we can easily test K8GB's integrations with upstream DNS providers.
The K8GB maintainers don't have have in their company environment to all the supported integrations, therefore there is the need to introduce guides to perform such testing.
We discussed that connecting a local kubernetes cluster to the cloud infrastructure would be the most cost-efficient solution since the DNS infrastructure is often quite cheap.