Read username from config, not from the system environment #36
Description
Changing the s3 bucket name from cloudexec-myname to cloudexec-mynewname is non-trivial as the username is read from the user running cloudexec.
Troublesome when a given bucket is stuck in the 7-day deletion purgatory, for example. Or when someone wants to maintain two separate buckets for two separate types of work.
Cloudexec should read this namespace from a config file instead of from the user's name to improve flexibility.