Add chains installation and notes.

chains/chains-config.yaml

@@ -0,0 +1,18 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  labels:
+    app.kubernetes.io/instance: default
+    app.kubernetes.io/part-of: tekton-chains
+  name: chains-config
+  namespace: tekton-chains
+data:
+   artifacts.taskrun.format: in-toto
+   artifacts.taskrun.storage: tekton
+   artifacts.taskrun.signer: x509
+   artifacts.pipelinerun.format: in-toto
+   artifacts.pipelinerun.storage: tekton
+   artifacts.pipelinerun.signer: x509
+   artifacts.oci.storage: tekton
+   artifacts.oci.signer: x509
+   builder.id: http://tekton.internal.jpace121.net