Option to run GC for a desired forecast length, hera and cloud cronjob

[SadeghTabas-NOAA]

Currently we can run graphcast for 40 time steps on cloud machines. However, we need to get forecasts for longer (e.g., 16 days similar to GEFS) or shorter period (for the case of debugging). In addition, there are some issues with running graphcast on hera as hera does not have internet on the compute node. Once these issues resolved, the cronjob should be scheduled and upload realtime forecast on the following s3 bucket:
https://noaa-nws-graphcastgfs-pds.s3.amazonaws.com/index.html