Add support for Style Guides API

[andrii-bodnar]

The Crowdin API introduces a new Style Guides section. API client libraries should be updated to expose the Style Guides endpoints so that consumers can manage style guides (list, create, get, edit, delete) via the SDK.

References:

• Style Guides

[bulat3103]

Hi! I want to do this issue

[bulat3103]

Hi! I prepared PR #369