This commit adds the additional `-f` force command to all uses of `conda
clean --all` through the repo. Size should be smaller, but still testing
if anything breaks. See issue #861.

The last commit was only for the base-notebook's Dockerfile. For this,
all the files in the repo were grepped through and changed.

Following the discussion in issue #861, this changes the `conda clean`
flags.

Add vulnerability reporting info

https://discourse.jupyter.org/t/responsible-vulnerability-reporting/655

Update to Spark 2.4.1

https://www.apache.org/dist/spark/spark-2.4.1/spark-2.4.1-bin-hadoop2.7.tgz.sha512

The mirror we prefer no longer has 2.4.0

Disable su/sudo access unless sudo explicitly enabled for a specific user using GRANT_SUDO.

Added s3 + spark session instructions

Manpage recipe

bump notebook, jupyterhub

with security fixes

Add DockerHub-links to README.md

Move tzdata to minimal-notebook and document it

Add link to Discourse

chown: add logging and a test

Signed-off-by: Brett Randall <javabrett@gmail.com>

Signed-off-by: Brett Randall <javabrett@gmail.com>

Signed-off-by: Brett Randall <javabrett@gmail.com>

[ci skip] stderr when no tty

[ci skip] Fix spark version check

Not in PATH

[ci skip] Improve manifests, update index page

[ci skip] Add package manifest support

Generates manifest pages and pushes them
to the docker-stacks GitHub wiki.
Does not update a global index of all builds yet.

Enable color terminal in common cases