update the get_reseller_timezone.sh script

The get_reseller_timezone.sh currently references the ce.timeZone property in contenteditor.properties. This property was removed in Mercury, so we need a different way to get the reseller time zone. The only references I can find to this script are in admax-process.sh and admax-staging-process.sh. Both are used to get yesterday's date for the reseller time zone.

In both cases, we can get yesterday's date for the reseller by looking up their time zone with a SAPI web client by moving that logic out of bash and in to Java.