Update ReadMe regarding removal from CRAN

[geneorama]

To address the recent removal from CRAN update the ReadMe to inform users of the removal and provide:

1. Instructions for a workaround (downloading with devtools)
2. Steps being taken to address the issue and get RSocrata back on CRAN
3. Provide a best guess timeline

In normal scripts one would simply install with devtools::install_github("Chicago/RSocrata") rather than using install.packages("RSocrata"). Does anyone (@nicklucius ?) have further suggestions regarding instructions for installation scripts that may be deployed with containerization or other use cases?

Some quick googling led me to https://www.r-bloggers.com/2019/02/running-your-r-script-in-docker/. This has very clean and very normal looking Docker instructions. They are using R or Rscript to install packages, which I think is the most normal way. In the past I have installed packages from the command line using apt, but I don't even remember how or why, and I don't see examples of that now. So unless someone speaks up, I won't worry about that potential edge case.

@nicklucius @tomschenkjr I plan to push up a new readme under a branch issue216

[geneorama]

#215 #214 Thank you for the report, we will be updating the ReadMe as soon as possible.