[eventlet-deprecation] Add a reference document

Related-Bug: #2069831
Change-Id: I565d02e6760406d0bbd08e6d4dfb2bbef206cfdb

doc/source/eventlet_deprecation/index.rst

@@ -0,0 +1,28 @@
+..
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+      Convention for heading levels in Neutron devref:
+      =======  Heading 0 (reserved for the title in a document)
+      -------  Heading 1
+      ~~~~~~~  Heading 2
+      +++++++  Heading 3
+      '''''''  Heading 4
+      (Avoid deeper levels because they do not render well.)
+
+==============================
+Eventlet Deprecation Reference
+==============================
+
+This document contains the information related to the ``eventlet`` library
+deprecation. Each section describes how each module has been migrated, the
+caveats, the pending technical debt and the missing parts.

doc/source/index.rst

@@ -77,6 +77,14 @@ Contributor Guide
 
    contributor/index
 
+Eventlet deprecation
+--------------------
+
+.. toctree::
+   :maxdepth: 2
+
+   eventlet_deprecation/index
+
 API Reference
 -------------