Split store codes into separate crate

[Farhad-Shabani]

Problem Statement

During my work on developing a mock Cosmos chain for the Hermes relayer-next (this issue), I observed that the current repository structure could potentially create circular dependencies for projects aiming to utilize store types and implementation. Additionally, this forces projects to include unnecessary library parts, even if they only need the store parts.

To address this, it is suggested we split the store code from the application and maintain it as a distinct crate.

This separation would also facilitate the development of a new mock module in ibc-rs. Consequently, to benefit from the AVL store implementation, we will only have to import the basecoin_store library without the need to rely on any application-related code.