Split CI manifests and user-facing examples

Currently, some files in https://github.com/kubermatic/machine-controller/tree/main/examples are used for e2e tests and are also presented as user-facing examples [in our README](https://github.com/kubermatic/machine-controller#deploy-machine-controller).

This causes problems because we tend to update examples to work for e2e tests, but that can break their compatibility with the latest released version (the `latest` tag points to the last release we published). This happened e.g. with the logging flags and results in invalid example files, as seen in #1655.

We should split the manifests used for CI and presented as user-facing deployment method, since the user-facing ones should always work with the latest release, but the ones used by CI should work with the `main` branch HEAD.

Start in the examples directory and the README section linked under “deploy machine controller,” then review the CI references that consume those manifests. Use #1655 as context for the compatibility problem. Done means CI manifests can track main while the user-facing examples remain valid with the latest released version.

Written by the indexing model from the issue text.