Update new state creation method to take an additional parameter
with the PKCE code verifier 's value and store it in the state
value.

The method will try to generate a code verifier (a random ASCII string)
and a code challenge (SHA256 hash of the verifier) and return an
array with them and the method use to create the code challenge.

If the code verifier generation fails the method will return false.

This is the first step when integrating PKCE into the authentication
workflow. When building the authentication URL a new code verifier
and challenge are created, the code verifier is store in the state
to be accessible at a later stage and the challenge is added as a
query param to the URL along side the method use to generate the
challenge from the verifier.

This is the second step when integrating PKCE into the authentication
workflow. Add the code verifier to the auth token request's body.
Code verifier is retieved from the state object created when building
the authentication URL.