Enhance documentation for querying account information with SDKs

* Added comprehensive guide on querying account information using five popular SDKs: Polkadot API (PAPI), Polkadot.js API, Dedot, Python Substrate Interface, and Subxt.
* Included prerequisites, environment setup, and runnable examples for each SDK.
* Clarified account data fields and provided next steps for users.

Author: nhussein11