I read a good article how make OAuth2 authorization without external libraries: https://medium.com/swlh/how-to-build-an-ios-app-with-oauth2-authentication-flow-github-example-part-1-ca4be718d5c4
And had going to repeat this, but on VK authorization. During the work,
I discovered that vk api don't allow custom redirect urls for standalone apps.
The task became more simply: open webView and parse token from url after authorization.
For use received token I create simple TableView like https://github.com/evgenvanzhukov/DI-tutorial for show friend list obtained by api.vk.com
