Unique alphanumeric IDs for content sets

As pointed out by frankcarey, a consistent unique identifier for content sets will aid in terms of consistent and readable map and message tables. It also may be helpful for [issue to be linked shortly]. A new field will be added and initialized to the mcsid, so tables will not have to be renamed automatically. This field will be required when adding content sets, and changing the field for a content set will rename the associated map and message tables.