Fixes configuration is missing when rendering avatar.

Signed-off-by: crynobone <crynobone@gmail.com>
Move `Orchestra\Avatar\GravatarHandler::setIdentifierFromUser()` to `Orchestra\Avatar\Abstractable\AbstractableHandler`.

Signed-off-by: crynobone <crynobone@gmail.com>
Improve test case.

Signed-off-by: crynobone <crynobone@gmail.com>