Feature: GridSelection separation from lexical core

[icrosil]

Why

GridSelection creates unnecessary complexities within code by increasing bundle size and providing functionality that is not required from core use cases. In addition current Selection architecture (BaseSelection, RangeSelection, NodeSelection, GridSelection) used regularly with if conditions and multiple actions based on the selection type.

All of the reasons above are concluding that Selection approach should be refactored with goal of removing GridSelection from core package.

Approach

On internal disucssion with @zurfyx and @fantactuka we've aligned on next steps:

• gradually moving code away from practices of "| RangeSelection | NodeSelection | GridSelection"
• removing / deprecating pieces of code that are outdated , or should be covered by one of the selections directly
• Move GridSelection to a Tables package

Notes

• Created issue for visibility purpose, so all of upcoming discussions can be done here.
• All the PRs will be linked here as work will be completed in a several stages.

[HoaPhamThi]

i am using lexical version 0.12.5, why can't i find GridSelection and $isGridSelection in lexical/table