[skip ci] Fix JUPYTER_ENABLE_LAB example

Fixes #724

JUPYTER_ENABLE_LAB documented as JUPYTER_LAB_ENABLE

The documentation in common.md references option JUPYTER_LAB_ENABLE, which does nothing. The correct name for this option is JUPYTER_ENABLE_LAB.

Bump to latest point releases

Add note for launching notebook with no token

Changed Dockerfile for USER/ID/GID to be Docker build arguments

Convert FROM specification to ARG (#727)

Fix the common options link in the docs

Fix launch command in docs

Closes #724

Closes #728

Point badges to dockerhub, add alt-text to microbadger

* status, pulls badges now point to https://hub.docker.com/r/jupyter/tensorflow-notebook/
* microbadger badges now have 'image metadata' alt text

* status, pulls badges now point to https://hub.docker.com/r/jupyter/scipy-notebook/
* microbadger badges now have 'image metadata' alt text

* status, pulls badges now point to https://hub.docker.com/r/jupyter/r-notebook/
* microbadger badges now have 'image metadata' alt text

* status, pulls badges now point to https://hub.docker.com/r/jupyter/pyspark-notebook/
* microbadger badges now have 'image metadata' alt text

* status, pulls badges now point to https://hub.docker.com/r/jupyter/datascience-notebook/
* microbadger badges now have 'image metadata' alt text

* status, pulls badges now point to https://hub.docker.com/r/jupyter/all-spark-notebook/
* microbadger badges now have 'image metadata' alt text

Updates:

* Currently clicking on the pulls & stars badges directs users to the actual button svg image source. The link should point to https://hub.docker.com/r/jupyter/minimal-notebook/.
* Add alt-text "image metadata" to microbadger badge

Fix builds by updating to compatible versions

The RC1 contains the fix to support latest release of JupyterLab.

Fixes #710

Update docs about NB_USER set up

Update jupyter_notebook_config.py to fix bug introduced in notebook 5.7.0