Update openid example (#2474)

* Update openid example

* Trim unnecessary deps

* Update serve instructions

* Remove unnecessary version in patch directive

* Remove outdated workspace instructions

* use storage signals instead of global signals with manual synchronization

---------

Co-authored-by: Evan Almloff <evanalmloff@gmail.com>

examples/openid_connect_demo/.cargo/config.toml

@@ -0,0 +1,5 @@
+[env]
+DIOXUS_FRONT_ISSUER_URL = "TODO"
+DIOXUS_FRONT_CLIENT_ID = "TODO"
+DIOXUS_FRONT_CLIENT_SECRET = "TODO"
+DIOXUS_FRONT_URL = "http://localhost:8080"