Add Documentation for File-Based Configuration

[ysolomchenko]

Blocked by

• Create an Infrastructure of Classes for Configuration #4397
• Add Unit Tests for the YAML Deserializer #4398
• Add Mapping from Config Classes to Existing Settings #4399
• Add missing SDK-level configurations #4400

Description

Create documentation with examples of file-based configuration, demonstrating correct usage, supported formats, and environment variable overrides.

Acceptance Criteria

• Documentation clearly explains the file-based configuration format.
• Environment variable substitution is demonstrated and explained.
• Documentation is reviewed and approved for accuracy and clarity.