Adds config file initialization

Adds the initial creation of the configuration file
jupyter_notebook_config.json to the image. This file
was missing as reported in issue #639 and caused an
error when trying to set a new password via the Web
interface.

Bumps the version of Jupyter Notebook to 5.6

Updates Apache Mirror URL because the current causes build timeouts

The mirror used now (mirrors.ukfast.co.uk) is fast enough and does not
point to an ad site and is already used in a different Dockerfile within
this repository.

base-notebook/Dockerfile

@@ -79,14 +79,20 @@ RUN cd /tmp && \
     fix-permissions $CONDA_DIR && \
     fix-permissions /home/$NB_USER
 
-# Install Jupyter Notebook and Hub
+# Install Jupyter Notebook, Lab, and Hub
+# Generate a notebook server config
+# Cleanup temporary files
+# Correct permissions
+# Do all this in a single RUN command to avoid duplicating all of the
+# files across image layers when the permissions change
 RUN conda install --quiet --yes \
-    'notebook=5.5.*' \
+    'notebook=5.6.*' \
     'jupyterhub=0.8.*' \
     'jupyterlab=0.32.*' && \
     conda clean -tipsy && \
     jupyter labextension install @jupyterlab/hub-extension@^0.8.1 && \
     npm cache clean --force && \
+    jupyter notebook --generate-config && \
     rm -rf $CONDA_DIR/share/jupyter/lab/staging && \
     rm -rf /home/$NB_USER/.cache/yarn && \
     fix-permissions $CONDA_DIR && \

pyspark-notebook/Dockerfile

@@ -16,7 +16,7 @@ RUN apt-get -y update && \
     rm -rf /var/lib/apt/lists/*
 
 RUN cd /tmp && \
-        wget -q http://apache.claz.org/spark/spark-${APACHE_SPARK_VERSION}/spark-${APACHE_SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz && \
+        wget -q http://mirrors.ukfast.co.uk/sites/ftp.apache.org/spark/spark-${APACHE_SPARK_VERSION}/spark-${APACHE_SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz && \
         echo "DC3A97F3D99791D363E4F70A622B84D6E313BD852F6FDBC777D31EAB44CBC112CEEAA20F7BF835492FB654F48AE57E9969F93D3B0E6EC92076D1C5E1B40B4696 *spark-${APACHE_SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz" | sha512sum -c - && \
         tar xzf spark-${APACHE_SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz -C /usr/local --owner root --group root --no-same-owner && \
         rm spark-${APACHE_SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz