All sample READMEs -- modified /selfservice endpoint to / (plus format-only change in fullstack README file)

[OPENIDM-3463]Update openidmui -> selfservice, integrators guide

[OPENIDM-3479] Update openidmui -> selfservice, READMEs (also changed mydomain.com -> example.com per RFC2606))

use appropriate FQDNs in full stack sample

Correct typos, path errors in fullStack sample README

FullStack sample README -- correct typo in path to authentication.json

OPENIDM-2761...OpenAM Session Module UI integration includes "fullStack" sample which demonstrates how to effectively use IDM, DJ, and AM together reviewed at CR-6042