add logs to the staged_root output

RStudio server has a log output that's currently held within the container (or somewhere else if run on kuberenetes).

Let's make sure that log gets put into staged_root so that we can debug errors like 502s when customers run into errors.

Anything writing to Kubernetes logs accessible via stdout/stderr and kubectl logs gets written to pod.log:

bc_osc_rstudio_server/template/before.sh.erb

Lines 2 to 3 in 9ec8ea2

    
           <% if context.cluster =~ /kubernetes/ -%> 
        
           exec &> >(tee -a "pod.log")

If there is a log file written, it's not being explicitly set at this time as far as I can tell.

Yea they're not stdout/err, IIRC it's a /var/log location.

Not sure how that's possible since /var/log won't be writable by the user, it will only be writable by root. I would think best solution for wherever it gets written to to pass a flag (hopefully possible) to RStudio to force it to use staged_root for the logs.

I see this for rsession help output:

log:
  --log-stderr arg (=0)                 write log entries to stderr

That could be useful.

I don't see anything useful for the rserver command when running the help output.

	<% if context.cluster =~ /kubernetes/ -%>
	exec &> >(tee -a "pod.log")