[ParentData] Rewrite Parent Data code

[sctop]

ParentData was first introduced to solve the problem that "a child could not access its parents' data". With ParentData, a parent can pass its own data (e.g. name and namespace) to their children, so that children can access them for later use.

Currently, ParentData is used primarily in event entries, where an event story/battle/ui needs to know its parents, to be able to display their parents' names (i.e. the event name).

The issue with ParentData is how messy the code is. We've observed that a parent can exist multiple times when data is exported, creating a completely unnecessary and ugly structure due to poor code lines. Therefore the code needs to be rewritten in a clearer and non-buggy way.

Expecting the rewriting will be in place in September or October this year.

BE ADVISED: I personally DO NOT recommend other people to touch the code because I CAN NOT EVEN figure out what exactly it is!