[DOC] Update London OOM documentation

Add information:
- new Deployment options (Production, Development)
- move Istio deployment to base installation
- add Gateway-API and Keycloak Installation instructions
- split and rename of a few files for updated structure
- changed rst section formatting as suggested in sphinx rtd theme
- add London Release Notes

Issue-ID: OOM-3159

Signed-off-by: Andreas Geissler <andreas-geissler@telekom.de>
Change-Id: I98b8541d51daba982fd6c8be0c85fae676d53c13
diff --git a/docs/sections/guides/infra_guides/oom_infra.rst b/docs/sections/guides/infra_guides/oom_infra.rst
new file mode 100644
index 0000000..ddc00b6
--- /dev/null
+++ b/docs/sections/guides/infra_guides/oom_infra.rst
@@ -0,0 +1,34 @@
+.. This work is licensed under a Creative Commons Attribution 4.0
+.. International License.
+.. http://creativecommons.org/licenses/by/4.0
+.. Copyright (C) 2022 Nordix Foundation
+
+.. Links
+.. _Kubernetes: https://kubernetes.io/
+
+
+.. _oom_infra_guide:
+
+OOM Infrastructure Guide
+========================
+
+.. figure:: ../../resources/images/oom_logo/oomLogoV2-medium.png
+   :align: right
+
+OOM deploys and manages ONAP on a pre-established Kubernetes_ cluster - the
+creation of this cluster is outside of the scope of the OOM project as there
+are many options including public clouds with pre-established environments.
+If creation of a Kubernetes cluster is required, the life-cycle of this
+cluster is independent of the life-cycle of the ONAP components themselves.
+
+For more information about functionality and processes please refer to the
+following documents:
+
+.. toctree::
+  :maxdepth: 1
+
+  oom_infra_deployment_options.rst
+  oom_infra_deployment_requirements.rst
+  oom_infra_base_config_setup.rst
+  oom_infra_optional_addons.rst
+  oom_infra_ingres_controller_setup.rst