Make Session implement ISessionInfo

[RubenVerborgh]

As discussed in https://github.com/inrupt/solid-client-authn-js/issues/567, we currently have an inconvenient session.info field.

I propose to:

• [ ] make Session implement ISessionInfo to avoid this detour
• [ ] (optional) create an ISession interface, which is what Session implements
• [ ] have handleIncomingRedirect return Session (ISession) rather than ISessionInfo
• [ ] deprecate Session#info so we can remove it in a future version
• [ ] change all ISessionInfoXxx classes and interfaces to return Session (ISession) instead of ISessionInfo
  • [ ] with the next semver.major release, rename those classes into ISessionXxx instead