This is a fast implementation of list crdt operations without performance optimizations
The purpose of this pr is to compare the implementation of YText and YArray, and try to abstract general utility functions

This pr contains 2 parts:

1. ✅ MarkerList, the purpose of this List is to record the adjacent index of the item in the list, so as to facilitate quick search in the linked list. In the original yjs implementation, based on the self-incrementing timestamp field, the effect similar to Pooled Cache is achieved. In our implementation, LinkedList is used instead. Rust does not need to worry about the performance loss caused by GC.
2. 🚧 ListCore is an abstraction of list crdt operations. It treats the CrdtItem linked list as a List for CRUD, and the upper layer YArray/YXmlFragment is then encapsulated based on ListCore

• ✅ read: get/iter
• write: insert/insertAfter/push/delete