adds serverTime and field on json export

[johnbaker]

The following issue details the current issue with the date and time field in the data:
#187

This pull request doesn't solve the display issue as care would need to be taken with old data (without the actual serverTime value) and could lead to confusion. However, as a short-term solution for applications that may either parse the RCLootCouncil.lua saved variable or use the Json export, this pull request adds a "serverTime" field to the loot data using the GetServerTime() function which is synchronized across clients and not effected by the current user's system clock or time zone.

I didn't include the EQXML export as the and timestamps are only based on the day (and not time) and dynamically swapping between the date/time epoch and the actual server epoch based on its existence may not desired. I can add this if requested.

[evil-morfar]

Thanks for your PR, but I'm not going to merge it currently, as a rework of everything time related is on my schedule for patch 11.1. This includes switching time stamps to be server time based, and compared to this, doesn't need extra data storage.

I'm gonna leave this as is in case anyone needs it, and with a promise of implementing it for patch 11.1 if for whatever reason I'm not able to do my planned implementation.