Prepare release note for R1.0

We made a technical problem releasing lot of breaking changes in 0.99,
but that was necessary due to inability to build RC. In order to log
things properly create an explanational releasenote describing issues
and repeating major stuff.

Change-Id: I34d68d2d22d0a5a221d976713ec7a0db4745b299

releasenotes/notes/r1-d4efe289ebf0cbcd.yaml

@@ -0,0 +1,40 @@
+---
+prelude: >
+    This is a final R1.0 release of the OpenStackSDK. A few technical issues
+    caused us not to reach this milestone cleanly, therefore we decided to one
+    more time explicitly log everything what should be considered as R1.0. For
+    detailed list of changes please see individual release notes from 0.99.0 to
+    0.103.0. Most important changes are explicitly repeated here.  There were
+    issues with maintainability of multiple available access interfaces, which
+    forced us to consider what we are able to maintain in the long run and what
+    we can not. That means that certain things were dropped, which is why we
+    are releasing this as a major release.  R1.0 is considered as a first major
+    release with corresponding promise regarding backwards-compatibility.
+features:
+  - |
+    Cloud layer is now consistently returning ``Resource`` class objects.
+    Previously this was not always the case.
+  - |
+    API response caching is implemented deep inside the code which will
+    minimize roundtrips for repeated requests.
+  - |
+    The majority of services were verified and adapted to the latest state of
+    the API.
+  - |
+    Certain code reorganization to further help in code reduction has been made
+    (metadata, tag and quota support moved to standalone common classes).
+upgrade:
+  - |
+    Cloud layer methods are returning ``Resource`` class objects instead of
+    ``Munch`` objects.  In some cases this cause renaming of the attributes.
+    ``Resource`` class is ``Munch`` compatible and allows both dictionary and
+    attribute base access.
+  - |
+    Some historical methods, which were never properly tested were dropped.
+deprecations:
+  - |
+    ``Munch`` is dropped as a dependency. The project has no releases since
+    multiple years and was causing huge performance impact already during
+    import. This has directly no negative imapct to SDK users (it now starts
+    faster), but in the code we copied used ``Munch`` pieces. They are going to
+    be consistently eliminated in next releases.