docs: add tutorial and how-to for installing airgapped Omni

Add a tutorial for installing a suite of applications which makes Omni usable in an airgapped environement:
- Installation of Gitea
- Installation of Keycloak
- Installation of Omni

This includes a separate how-to guide on the configuration of Keycloak for it's integration with Omni SAML.

Signed-off-by: Christian Rolland <[email protected]>

Author: ro11net

content/docs/how-to-guides/how-to-configure-keycloak-for-omni/_index.md

@@ -0,0 +1,97 @@
+---
+title: "How to Configure Keycloak for Omni"
+draft: false
+weight: 220
+---
+
+1. Log in to Keycloak.
+
+2. Create a realm.
+
+- In the upper left corner of the page, select the dropdown where it says **master**
+
+
+{{< imgproc keycloak_001.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Fill in the **realm name** and select **create**
+
+{{< imgproc keycloak_002.png Resize "900x" >}}
+{{< /imgproc >}}
+
+3. Find the realm metadata.
+
+- In the realm settings, there is a link to the metadata needed for SAML under Endpoints.
+    - Copy the link or save the data to a file. It will be needed for the installation of Omni.
+
+{{< imgproc keycloak_003.png Resize "900x" >}}
+{{< /imgproc >}}
+
+4. Create a client
+
+- Select the **Clients** tab on the left
+
+{{< imgproc keycloak_004.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Fill in the **General Settings** as shown in the example below. **Replace the hostname in the example with your own Omni hostname or IP**.
+    - Client type
+    - Client ID
+    - Name
+
+{{< imgproc keycloak_005.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Fill in the **Login settings** as shown in the example below. **Replace the hostname in the example with your own Omni hostname or IP**.
+    - Root URL
+    - Valid redirect URIs
+    - Master SAML PRocessing URL
+
+{{< imgproc keycloak_006.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Modify the **Signature and Encryption** settings.
+    - Sign documents: **off**
+    - Sign assertions: **on**
+
+{{< imgproc keycloak_007.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Set the **Client signature required** value to **off**.
+
+{{< imgproc keycloak_008.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Modify **Client Scopes**
+
+{{< imgproc keycloak_009.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Select **Add predefined mapper**. 
+
+{{< imgproc keycloak_010.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- The following mappers need to be added because they will be used by Omni will use these attributes for assigning permissions.
+    - X500 email
+    - X500 givenName
+    - X500 surname
+
+{{< imgproc keycloak_011.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Add a new user (optional)
+    - If Keycloak is being used as an Identity Provider, users can be created here.
+
+{{< imgproc keycloak_012.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Enter the **user information** and set the **Email verified** to **Yes**
+
+{{< imgproc keycloak_013.png Resize "900x" >}}
+{{< /imgproc >}}
+
+- Set a password for the user.
+
+{{< imgproc keycloak_014.png Resize "900x" >}}
+{{< /imgproc >}}