Remove sparklyr from datascience notebook

[romainx]

Hello,

r-sparklyr was installed in the datascience-notebook but Spark was not installed. So IMHO this does not make sense -- I figured this out during the PR #1000 .

library(sparklyr)
sc <- spark_connect(master = "local")

# Error in spark_install_find(version, hadoop_version, latest = FALSE, hint = TRUE): Spark version not installed. To install, use spark_install()

So, I've simply removed it.

Best.

[parente]

I noticed the data science image build failed yesterday on docket hub. I haven’t looked at why yet so I’m going to hold off on merging this PR until I do. Thanks for submitting it.

[parente]

The build is fixed. Merging. Thank you!