Update README.md with a description of the console

This is an initial version that will be there for a few next weeks while
the project is bootstrapping.

README.md

-# kubernetes-console
+# Kubernetes Console
+Kubernetes Console is a general purpose, web-based UI for Kubernetes clusters. It allows to manage applications running in the cluster, troubleshoot them, as well as, manage the cluster itself.
+
+The console is currently under active development and is not ready for production use (yet!).
+