Move internal to pkg to allow library re-use

[maordavidov]

The usage of internal does not allow us to re-use the packages in other go applications. Changing to pkg will allow us to reference the source code in other applications as well.

[mbilski]

Hi @maordavidov

We are using the internal on purpose. That way, we are not obligated to maintain backward compatibility, and we can make any changes we want there.

What functionalities are you looking for to re-use from the oauth2c internal package? I would instead expose only some of the internal functionalities in pkg using a new abstract interface so that way we can limit the api we need to keep backward compatible to a bare minimum.

[maordavidov]

I see, in that case I will close the PR, I already found a workaround to use the entire command as sub command and forward the stdout.