A new IdentityInterface for authentication

[weierophinney]

This PR is a work in progress to solve the issue about OAuth2 client authentication reported in zendframework/zend-expressive-authentication-oauth2#55. The idea is to use a general IdentityInterface as follows:

namespace Zend\Expressive\Authentication;

interface IdentityInterface
{
    /**
     * Get the unique identity
     */
    public function getIdentity() : string;
}

And a specific UserInterface that extends the IdentityInterface, as follows:

namespace Zend\Expressive\Authentication;

interface UserInterface extends IdentityInterface
{
    /**
     * Get all user roles
     *
     * @return Iterable
     */
    public function getRoles() : iterable;

    /**
     * Get a detail $name if present, $default otherwise
     */
    public function getDetail(string $name, $default = null);

    /**
     * Get all the details, if any
     */
    public function getDetails() : array;
}

Regarding the AuthenticationMiddleware, this PR generates a UserInterface PSR-7 attribute if authenticate($request) returns an instance of UserInterface. Otherwise, it will returns a IdentityInterface attribute.

These changes should prevent BC breaks for existing implementations using zend-expressive-authentication and offers a new solution to zend-expressive-authentication-oauth2 for implementing a ClientInterface (extending IdentityInterface).

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Originally posted by @ezimuel at zendframework/zend-expressive-authentication#39

[weierophinney]

@ezimuel Is there still work to do on this patch?

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Originally posted by @weierophinney at zendframework/zend-expressive-authentication#39 (comment)

[weierophinney]

sorry for the super late response - LGTM 👍

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Originally posted by @marc-mabe at zendframework/zend-expressive-authentication#39 (comment)

[weierophinney]

@ezimuel Is there still work to do on this patch?

@weierophinney this PR is ready, of course we need to implement a new ClientInterface for zend-expressive-authentication-oauth2 to solve zendframework/zend-expressive-authentication-oauth2#55

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Originally posted by @ezimuel at zendframework/zend-expressive-authentication#39 (comment)

[weierophinney]

I've got this and the related one for oauth2 on my todo list - not sure if I'll have time to evaluate them this week, or if it will be early next. I'll drop a note with what route I go (new minor or new major) when I do.

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Originally posted by @weierophinney at zendframework/zend-expressive-authentication#39 (comment)