Split query file into logical submodules

[akorchyn]

Module Organization and Naming Clarity

Description

The current module structure could benefit from better organization. At ~800 lines, it's not overly large, but the naming conventions make it difficult to distinguish between similar components (QueryBuilder, RpcBuilder, RpcHandler, RpcRequest, RpcRequestHandler, MultiRpcBuilder, etc.).

Proposed Solution

Consider splitting the module into smaller sub-modules organized by:

1. Core traits that items implement
2. Logical categories (potentially with nested layers)

Example Structure

near_api::common::query::<module_name>         # Core implementations
near_api::common::query::<module_name>::aliases # Aliases like QueryBuilder

This would make it easier to differentiate between related components like RpcBuilder and MultiRpcBuilder and their respective aliases.

Additional Context

Originally discussed in PR #45: #45 (comment)