base image docs, remove CI (#2231)

Author: skudasov

.github/workflows/k8s-publish-test-base-image.yml

@@ -1,5 +1,5 @@
 # base test for all k8s test runs
-FROM golang:bullseye
+FROM golang:1.25.3-bookworm
 
 ARG BASE_URL
 ARG HELM_VERSION

lib/k8s/Dockerfile.base

@@ -0,0 +1,10 @@
+.PHONY: build
+build:
+	docker build --platform linux/amd64 -t test-base-image -f Dockerfile.base .
+
+.PHONY: push
+push:
+	@if [ -z "$(registry)" ]; then echo "Error: registry variable is not set. Please provide it with 'make push registry=...'. See README.md explaining where to get it."; exit 1; fi
+	aws ecr get-login-password --region us-west-2 | docker login --username AWS --password-stdin $(registry).dkr.ecr.us-west-2.amazonaws.com
+	docker tag test-base-image:latest $(registry).dkr.ecr.us-west-2.amazonaws.com/test-base-image:latest
+	docker push $(registry).dkr.ecr.us-west-2.amazonaws.com/test-base-image:latest

lib/k8s/Makefile

@@ -1,3 +1,22 @@
 # K8s Deployment (Deprecated)
 
-[![Documentation](https://img.shields.io/badge/Documentation-MDBook-blue?style=for-the-badge)](https://smartcontractkit.github.io/chainlink-testing-framework/lib/k8s/KUBERNETES.html)
+[![Documentation](https://img.shields.io/badge/Documentation-MDBook-blue?style=for-the-badge)](https://smartcontractkit.github.io/chainlink-testing-framework/lib/k8s/KUBERNETES.html)
+
+## K8s Framework Sunsetting
+
+We were using this `K8s` framework specifically in `sdlc` cluster but after migration to `main.stage` we use it only on-demand for some legacy tests.
+
+### Building Base Image for K8s Tests
+This is rarely required, but sometimes infrequent updates are needed.
+
+Go to SSO [home](https://sso.smartcontract.com/app/UserHome) and find `AWS -> secure-sdlc`, copy the registry ID
+```
+<sdlc_registry_id> | [email protected]
+```
+use creds for this account in your terminal, paste the <sdlc_registry_id> then build and push the image.
+
+```bash
+make build
+make push registry=<sdlc_registry_id>
+```
+