Move readme to devops tools doc

README.md

-# Usage
-
-Register a runner with GitLab Runner and configure it like this:
-
-```
-[[runners]]
-  name = "DrupalCI"
-  url = "https://your.gitlab.url/"
-  token = "..."
-  executor = "docker"
-  [runners.docker]
-    tls_verify = false
-    image = "registry.lakedrops.com/docker/gitlab-drupal-ci:php-7.2"
-    privileged = true
-    disable_entrypoint_overwrite = false
-    oom_kill_disable = false
-    disable_cache = false
-    volumes = ["/var/run/docker.sock:/var/run/docker.sock", "/cache"]
-    shm_size = 0
-  [runners.cache]
-    [runners.cache.s3]
-    [runners.cache.gcs]
-```
-
-# Node version
-
-When using node from within this framework, this defaults to version `12-stretch-slim` but you can change the default version by setting the environment variable `NODE_VERSION` to one of these tags:
-
-- 8-jessie-slim
-- 10-jessie-slim
-- 12-stretch-slim
-- 13-stretch-slim
-
-# Credit
-
-- [Image from jonaskello](https://github.com/jonaskello/docker-and-compose)
-- [Alpine glibc from sgerrand](https://github.com/sgerrand/alpine-pkg-glibc)