[lib] introduce generic StoreOperation type

Summary:
This is some kind of spec for data store. The purpose is to:

1. Cleanup by fitting up existing logic into this interface
2. Make a "contract" for needed utils for future Data Stores
3. I think it's better to use a method from descriptive object rather than calling random util functions

The only problem will be draftStore, which does nto not have those methods (the only thing I can do rn is to create a follow-up task to improve draft operations).

Examples of usage in following diffs.

Depends on D8617

Test Plan: Flow

Reviewers: michal, tomek, atul

Reviewed By: atul

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D8618