Refactoring `accounts` atoms

[pedrorezende]

This PR refactors all the accounts atoms, removing unused ones, and improving clarity to the existing ones. All the dependencies were changed accordingly. Also, it limits the balance to NAM tokens only, simplifying the existing code.

Fixes #840

[github-actions[bot]]

🚀 Deployed on https://pull-request-850--wallet-development-heliax-dev.netlify.app