[devtool] introduce datasink class to etdump (#8677)

Pull Request resolved: https://github.com/pytorch/executorch/pull/8496

this diff introduce datasink class, the class for managing the customized debug data storage pipeline.

Detials can be found in https://docs.google.com/document/d/1y_m32mKdj-OgLcLUz9TKhBW3PC3bBDYSBbeAH544EfM/edit?tab=t.0
ghstack-source-id: 268137338

Differential Revision: [D69583422](https://our.internmc.facebook.com/intern/diff/D69583422/)

Co-authored-by: gasoonjia <gasoonjia@icloud.com>
Co-authored-by: Scott Wolchok <swolchok@meta.com>