Implement Yaml Deserializer

[ysolomchenko]

Blocked by

• Vendor YamlDotNet package #4395

Description

Implement a YAML deserializer with extended functionality to support environment variable substitution and proper handling of default values.

Acceptance Criteria

• The deserializer should accept standard primitive and object values.
• The deserializer must not fail when encountering fields that do not exist in the target class and should handle them gracefully.
• The deserializer should support environment variable substitution in the form ${ENV_VAR}.
• The deserializer should support environment variable substitution with a default fallback in the form ${ENV_VAR:-value}, where value is used if ENV_VAR is null.
• The deserializer should allow creating an object with a default value from an empty YAML node, even if the property type is nullable.

Example:

field:

public class Configuration 
{
    [YamlMember(Alias = "field")]
    public FiledClass? Field{ get; set; } = new();
}

Expected output:

Field is instantiated with its default value.