docs: add docs on omni with external etcd

Signed-off-by: Amarachi Iheanacho <amarachi.iheanacho@siderolabs.com>

Author: Iheanacho-ai

omni.yaml

@@ -24,6 +24,7 @@ navigation:
             - "omni-deployment-options.mdx"
             - "omni-on-prem-hardware-requirements.mdx"
             - "run-omni-on-prem.mdx"
+            - "run-omni-external-etcd-database.mdx"
             - "run-omni-on-k8s.mdx"
             - "run-omni-airgapped.mdx"
             - "run-image-factory-on-prem.mdx"

public/docs.json

@@ -2192,6 +2192,7 @@
               "omni/self-hosted/omni-deployment-options",
               "omni/self-hosted/omni-on-prem-hardware-requirements",
               "omni/self-hosted/run-omni-on-prem",
+              "omni/self-hosted/run-omni-external-etcd-database",
               "omni/self-hosted/run-omni-on-k8s",
               "omni/self-hosted/run-omni-airgapped",
               "omni/self-hosted/run-image-factory-on-prem",