Dockerfile: Add a symbolically linked release Dockerfile

Introduce the operator-lifecycle-manager.Dockerfile that's symbolically
linked from the root Dockerfile.

This is likely only needed in the short term while we iron out the
upstream/downstream split, and needed as the openshift/release
ci-operator is expecting to build the OLM container image using the
operator-lifecycle-manager.Dockerfile (what's currently present in
openshfit/ocp-build-data for the OLM 4.8 images) and that file doesn't
exist anywhere in the repository.

Author: timflannagan

operator-lifecycle-manager.Dockerfile

@@ -0,0 +1 @@
+Dockerfile