[FEATURE] Add option to run JobAnalyzer.py on existing hourly_*.csv files

[cartalla]

Is your feature request related to a problem? Please describe.

If you ran JobAnalyzer.py on a job.csv file and forgot --starttime and --endtime then it would be nice to leverage the already parsed hourly jobs files so that all of the jobs don't have to be reparsed and analyzed.

Describe the solution you'd like
Currently, there is an option called hourly stats that parses hourly_stats.csv and regenerates the xlsx.
This is helpful if the code for the xlsx changes, but not if you need to refilter the job data.
Rename hourly_stats to hourly_stats_csv and update hourly_stats to parse all of the hourly files.