chore: update docs for group auth and readme for docs site (#540)

## Description
add docs for adding group auth to a package and warning that its still
an alpha capability. also add note to readme about doc site.

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Other (security config, docs update, etc)

## Checklist before merging

- [x] Test, docs, adr added or updated as needed
- [x] [Contributor
Guide](https://github.com/defenseunicorns/uds-template-capability/blob/main/CONTRIBUTING.md)
followed

README.md

@@ -1,5 +1,7 @@
 # Unicorn Delivery Service - Core (UDS Core)
 
+## [UDS Core Docs](https://uds.defenseunicorns.com/core/)
+
 UDS Core establishes a secure baseline for cloud-native systems and ships with compliance documentation and first-class support for airgap/egress-limited systems. Based on the work of [Platform One](https://p1.dso.mil), UDS Core expands on the security posture of [Big Bang](https://repo1.dso.mil/big-bang/bigbang) while providing advanced automation with the [UDS Operator](./src/pepr/operator/README.md) and [UDS Policy Engine](./src/pepr/policies/README.md). UDS Core is a collection of several individual applications combined into a single [Zarf](https://zarf.dev) package and we recommend using [UDS CLI](https://github.com/defenseunicorns/uds-cli?tab=readme-ov-file#install) to deploy it as a [UDS Bundle](#using-uds-core-in-production).
 
 #### tl;dr - [try it now](#quickstart)

docs/configuration/uds-operator.md

@@ -18,6 +18,12 @@ The UDS Operator plays a pivotal role in managing the lifecycle of UDS Package C
   - The operator creates targeted network policies for remote endpoints, such as `KubeAPI` and `CloudMetadata`. This approach aims to enhance policy management by reducing redundancy (DRY) and facilitating dynamic bindings in scenarios where static definitions are impractical.
 - **Creating Istio Virtual Services and Related Ingress Gateway Network Policies:**
   - In addition, the operator is responsible for generating Istio Virtual Services and the associated network policies for the ingress gateway.
+- **SSO Group Authentication:**
+  - Group authentication determines who can access the application based on keycloak group membership.
+  - At this time `anyOf` allows defining a list of groups, a user must belong to at least one of them.
+    {{% alert-caution %}}
+  Warning: **SSO Group Authentication** is in Alpha and may not be stable. Avoid using in production. Feedback is appreciated to improve reliability.
+    {{% /alert-caution %}}
 
 ### Example UDS Package CR
 
@@ -58,7 +64,10 @@ spec:
     - name: Grafana Dashboard
       clientId: uds-core-admin-grafana
       redirectUris:
-        - "https://grafana.admin.uds.dev/login/generic_oauth"
+        - "https://grafana.admin.{{ .Values.domain }}/login/generic_oauth"
+      groups:
+        anyOf:
+          - /UDS Core/Admin
 ```
 
 ## Exemption