CI-DOCS: Document build-component-images pipeline

[#177484205](https://www.pivotaltracker.com/story/show/177484205)

Co-authored-by: Jaskanwal Pawar <[email protected]>

ci/pipelines/build-component-images.md

@@ -0,0 +1,44 @@
+# build-component-images
+
+## Purpose
+This pipeline builds images that have not yet been moved to their own `cf-for-k8s-<component>-images` pipeline.
+
+## Groups
+- `all`: the default group that aggregates all the image build groups. With the completion of image build standardization this may again become the source of other image builds.
+- `statsd-exporter`: currently this is the only component image we build in the pipeline.
+
+## Image building
+This pipeline builds using the concourse [oci-build-task](https://github.com/vito/oci-build-task).
+
+The build image jobs also adds annotations to the images using [deplab](https://github.com/vmware-tanzu/dependency-labeler).
+
+## Pipeline management
+
+This pipeline is managed via the `ci/templates/build-component-images.yml` [ytt](https://github.com/vmware-tanzu/carvel-ytt) template. To make changes to the pipeline, update the template file (and its input values file `ci/inputs/build-component-images.yml`), then run the `ci/configure` script to render the template with ytt and apply the changes with the [fly cli](https://concourse-ci.org/fly.html).
+
+### Adding a new component
+
+To integrate a new component, update `ci/inputs/cf-for-k8s-contributions.yml` with a new element in the `releases` array:
+
+```
+components:
+
+...
+
+  - name: <component name>
+    release:
+      repository: <github release repo>
+      owner: <github org of release repo>
+    sources:
+      - repository: <github source repo>
+        owner: <github source repo org>
+    images:
+      - name: <image name>
+        dockerfile:
+          repository: <source repo from sources list>
+          path: <path in source repo to Dockerfile>
+        context:
+          repository: <source repo from sources list>
+          path: <path in source repo from which to run the docker build>
+        params: {<custom params for docker build>}
+```

ci/pipelines/cf-for-k8s-contributions.md

@@ -35,7 +35,7 @@ Once unit testing is complete, we validate a fresh install on [KinD](https://git
 
 PR validation matches the matrix tested in the `cf-for-k8s-main` pipeline. Note that a failed concourse job in the `pr-validation` group does not necessarily indicate action is required by pipeline maintainers. The failure is required to block acceptance testing on unit testing using a concourse passed constraint.
 
-## Notes
+## Pipeline Management
 
 This pipeline is managed via the `ci/templates/cf-for-k8s-contributions.yml` [ytt](https://github.com/vmware-tanzu/carvel-ytt) template. To make changes to the pipeline, update the template file (and its input values file `ci/inputs/cf-for-k8s-contributions.yml`), then run the `ci/configure` script to render the template with ytt and apply the changes with the [fly cli](https://concourse-ci.org/fly.html).