Make home for image-* component docs

This has a description of the controllers, and is where the API specs
and refs will get copied to.

Signed-off-by: Michael Bridgen <michael@weave.works>

docs/components/image/controller.md

@@ -0,0 +1,16 @@
+# Image reflector and automation controllers
+
+The image-reflector-controller and image-automation-controller work together to update a Git
+repository when new container images are available.
+
+- The image-reflector-controller scans image repositories and reflects the image metadata in
+  Kubernetes resources.
+- The image-automation-controller updates YAML files based on the latest images scanned, and commits
+  the changes to a given Git repository.
+
+Links:
+
+- Source code [fluxcd/image-reflector-controller](https://github.com/fluxcd/image-reflector-controller)
+- Reflector [specification docs](https://github.com/fluxcd/image-reflector-controller/tree/main/docs/spec)
+- Source code [fluxcd/image-automation-controller](https://github.com/fluxcd/image-automation-controller)
+- Automation [specification docs](https://github.com/fluxcd/image-automation-controller/tree/main/docs/spec)