Remove nodesource' nodejs

We get node from the default JupyterLab install, since that
comes from conda-forge. This was not the case when we started -
we installed JupyterLab with pip. We no longer need the nodesource
node.

All the env vars, etc should still work!

repo2docker/buildpacks/base.py

@@ -52,11 +52,6 @@ RUN groupadd \
         --uid ${NB_UID} \
         ${NB_USER}
 
-RUN wget --quiet -O - https://deb.nodesource.com/gpgkey/nodesource.gpg.key |  apt-key add - && \
-    DISTRO="bionic" && \
-    echo "deb https://deb.nodesource.com/node_14.x $DISTRO main" >> /etc/apt/sources.list.d/nodesource.list && \
-    echo "deb-src https://deb.nodesource.com/node_14.x $DISTRO main" >> /etc/apt/sources.list.d/nodesource.list
-
 # Base package installs are not super interesting to users, so hide their outputs
 # If install fails for some reason, errors will still be printed
 RUN apt-get -qq update && \
@@ -247,7 +242,6 @@ class BuildPack:
         return {
             # Utils!
             "less",
-            "nodejs",
             "unzip",
         }