break out the apt R install steps for debugging/unsticking

[shaneknapp]

see #5332

i was able to build the datahub image locally after breaking these apt-get installs out in to their own RUN blocks. not sure why that helped, but we can at least test that out in circleci.

[ryanlovett]

Sounds odd. I wonder if the base packages need to be ticked up.

After it is debugged, it’s a good idea to have the apt update and install on the same RUN: https://docs.docker.com/develop/develop-images/instructions/#apt-get

[shaneknapp]

Sounds odd. I wonder if the base packages need to be ticked up.

that's my guess... but still only a guess. :\

After it is debugged, it’s a good idea to have the apt update and install on the same RUN: https://docs.docker.com/develop/develop-images/instructions/#apt-get

word