RStudio: handle RStudio packaging change
RStudio: handle RStudio packaging change

* rsconnect no longer ships with rstudio
* intermittent devtools namespace errors during R installs when install
  packages done as a group corrected by splitting into multiple commands.

Signed-off-by: Thell Fowler <06141d626b16a5ce7662a8dbffed8bdddd3f868e@tbfowler.name>

Thell/dockerfiles