Add docker image for portability

[tyronechen]

Hi MBP, thanks for this useful tool

• Previously used the version from commit 173082f and found it very helpful
• Unfortunately ran into some libR.so issues during lattice compilation in some machines
  • if R version is not compiled with --enable-R-shlib
• Made this Docker image and github workflow to work around that
  • but note that the versions wont align 100% with renv
• Also added qs2

On an unrelated note, i saw that some paths were hardcoded in the latest commit post processing which results in the shiny app breaking
(I can open a separate pull request for this later on)

server.R:sc1conf = readRDS("sc1conf.rds")
ui.R:sc1conf = readRDS("sc1conf.rds")