Oidc Access Token Provider

I have now implemented quite a few times OidcTokenAccessProvider, for example here.

Despite it being almost trivial in the end user codebase it turns out that is difficult to refactor the mechanism up to this repository.
More specifically the challenges are:

• Access to an HttpClient (or RequestAdapter but I think there are a few gaps later on) - possibly we should be able to decide to use the same or a different one from the "normal" API calls
• encode a form body is pretty straightforward with a bare HTTP client, not sure how that looks like with bare Kiota without the generated classes
• decode a Json response
• etc...

I'm here looking for guidance on how we can approach the problem.
I have attempted at first to add an initialize method to AccessTokenProvider and to AuthenticationProvider so that it can be eventually triggered by the RequestAdapter implementation.
I started having too many things to pull in and thought that it was not a great design ...

Empieza leyendo las interfaces AccessTokenProvider, AuthenticationProvider y RequestAdapter; después, compara la implementación referenciada RHAccessTokenProvider. Aclara cómo deben exponerse el acceso HTTP, la codificación de formularios y la decodificación JSON sin clases generadas; el issue estará listo solo después de acordar el diseño de la API y la ruta de integración esperada.