Add get UserInfo feature

[EXayer]

Problem

Steam users can change their username, avatar, etc. The package provides these data after successful login. But what if user had logged in, before changed its profile data. The only solution to get fresh UserInfo data now is to make user re-login.

Solution

There is Steam Web API endpoint - [GetPlayerSummaries ]https://developer.valvesoftware.com/wiki/Steam_Web_API).