Enable All Launcher functions to login to remote RStudio instance by providing login(host, username, password)

[bschulth]

• Currently the rstudioapi launcher functions can only be invoked from within an RStudio UI session (because you need access to a login token)
  • You can't even launch jobs from a bash shell that is SSH'd into the same server as the Workbench UI because you don't have access to the Workbench UI access token...so you can't schedule jobs to run in the launcher.
• It would be nice to support the launcher apis being able to login to a remote/local RStudio Workbench instance(s) via (host, username, and password) and then invoke the job launcher (local, kubernetes)
• The use case for this is largely to schedule jobs
  • Either from a local crontab
  • Or, run code from RSConnect scheduled jobs onto one or more Remote RStudio Workbench environments.
    • The current Kubernetes enhancement to run RSConnect on kubernetes pods, does not satisfy the requirement of launching jobs into specific RStudio Workbench instances that have different accessibility (filers, runtimes) than does the RsConnect instance the job is being scheduled from.