Rename calico folder to use major version part

* Use just the major part for the calico version for folder naming.
* For any minor uprades, it will be just reference updates within manifests.
* When moving to major version, then we will add a new folder with
  that version naming (v4)

Change-Id: I1ee30af26c3030531ef719a3cb649fb999d0244c

manifests/composite/infra/kustomization.yaml

@@ -1,4 +1,4 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
-  - ../../function/cni/calico/v3.15
+  - ../../function/cni/calico/v3