Add jupyterlab_bokeh extension

Chown of home dir needs to be recursive

add r-htmltools pkg

Without the extension it is not possible to use all Bokeh functionalities in JupyterLab

Add instructions for enabling Jupyter Lab interface with OpenShift deployment.

Spark 2.3

Avoid placing anything under home directory in OpenShift deployments.

Add entries to passwd/group if running as user not in passwd file.

Sample builder scripts for build custom notebook images using Source-to-Image.

Avoid placing anything under home directory in OpenShift deployment example so can use it to mount volumes.

improve secure_path modification by storing in sudoers.d

Ensure directories/files under home directory are writable.

Templates for deploying Jupyter Notebooks to OpenShift.

Use NB_UID for USER statement in Dockerfile so deployment platform can verify that image doesn't run as root.

Use NB_UID for USER statement in Dockerfile so deployment platform can verify that image doesn't run as root.