Log in with OAuth2 providers

[duxet]

For beginning, we could start with Google, Facebook and Twitter. Probably we shall go with https://github.com/laravel/socialite unless there is a better choice.

[ghost]

I would like to work on this!

[duxet]

That's awesome :)

I will try to help with every question that might arise. There is a lot of not yet translated polish strings, but the code itself is 100% english, so i hope it won't be an issue.

[ghost]

Yeah sure 👍