Separate camp location per period

In most multi-period camps, the location information is not shared between the periods. However, historically, we have had only one set of location fields on the camp. These fields could be moved to the period entity.

Start by locating the camp and period entities and identify the existing camp-level location fields. Determine which location data must become period-specific, then trace the affected camp and period behavior to define the required model and persistence changes; done means each period can hold its own location without sharing it unintentionally.

Written by the indexing model from the issue text.