* [kube] use local image for kubernetes integration tests
This PR replaces the use of the `nginx:latest` Docker image in Kubernetes integration tests with a custom-built image based on `alpine:3.20.3`. This custom image includes a shell for `kubectl exec` integration tests and a compiled binary to act as an HTTP server.
This change addresses recent issues where test workflows failed due to problems downloading the `nginx` image.
* add information about the image
* source files from alpine cdn
* copy files from alpine
* Update fixtures/alpine/README.md
Co-authored-by: Alan Parra <alan.parra@goteleport.com>
* Update fixtures/alpine/README.md
Co-authored-by: Alan Parra <alan.parra@goteleport.com>
* source files from alpine cdn (again)
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Co-authored-by: Alan Parra <alan.parra@goteleport.com>
