Rename and added a robust error handling functionality to the R/assign_job_queue.R file functions

[Seyi007]

• Implement error handling for mapOption2Process, get_proc_medians, write_proc_medians_table, get_proc_weights, advanced_opts2est_walltime, assign_job_queue, and plot_estimated_walltimes .
• Validate input arguments for each function to ensure they meet expected criteria.
• Use tryCatch blocks to handle errors and warnings gracefully.
• Provide informative error messages and detailed logging where appropriate.
• Ensure functions fail gracefully and provide useful feedback.

Also renamed the functions to the following;
assign_job_queue -> assignJobQueue
make_opts2procs -> mapOption2Process
map_advanced_opts2procs -> mapAdvOption2Process
get_proc_medians - calculateProcessRuntime
write_proc_medians_table -> writeProcessRuntime2TSV
write_proc_medians_yml -> writeProcessRuntime2YML
get_proc_weights -> getProcessRuntimeWeights
advanced_opts2est_walltime -> calculateEstimatedWallTimeFromOpts
plot_estimated_walltimes -> plotEstimatedWallTimes

• Feature (adds or updates new capabilities)
• Bug fix (fixes an issue).
• Enhancement (adds functionality).
• Breaking change (these changes would cause existing functionality to not work as expected).

Checklist

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• I have added a test which covers the code changes found within this PR.
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• Reviewer assignment: @jananiravi @the-mayer