Dismantle DNS-backed key-value store, k-v.io

I'm no longer engaged on setting up k-v.io; I thought it'd be cool to
have a DNS-backed etcd implementation, but now I don't care anymore.

There were technical challenges, too: Specifically, updating values did
not play well with DNS caching — you'd get the old value after updating.

If the service became popular, I'd quickly run out of disk space on my
tiny cloud VMs.

The service would most likely be used by people doing data exfiltration
via DNS. I already have enough problems with sslip.io scammers — the
last thing I want is to sign up for dealing with k-v.io scammers.

This commit removes the etcd configuration, certificates, and pipelines.

ci/pipeline-sslip.io.yml

@@ -65,34 +65,6 @@ jobs:
     params:
       image: image/image
 
-- name: build-and-push-k-v.io-nginx
-  plan:
-  - get: sslip.io-release
-    trigger: true
-  - get: sslip.io
-  - task: build-task-image
-    privileged: true
-    config:
-      platform: linux
-      image_resource:
-        type: registry-image
-        source:
-          repository: concourse/oci-build-task
-      inputs:
-      - name: sslip.io
-      outputs:
-      - name: image
-      params:
-        CONTEXT: sslip.io/k8s/
-        DOCKERFILE: sslip.io/k8s/Dockerfile-k-v.io-nginx
-        IMAGE_PLATFORM: linux/arm64,linux/amd64
-        OUTPUT_OCI: true
-      run:
-        path: build
-  - put: k-v.io-nginx
-    params:
-      image: image/image
-
 - name: build-and-push-sslip.io-nginx
   plan:
   - get: sslip.io-release
@@ -143,16 +115,6 @@ resources:
   source:
     uri: https://github.com/cunnie/sslip.io.git
 
-# Where we will push the k-v.io nginx Docker image with HTML assets
-- name: k-v.io-nginx
-  type: registry-image
-  icon: docker
-  source:
-    repository: cunnie/k-v.io-nginx
-    username: cunnie
-    password: ((docker_token))
-    tag: latest
-
 # Where we will push the sslip.io nginx Docker image with HTML assets
 - name: sslip.io-nginx
   type: registry-image