doc: prepare for versioned release notes

Break out each version release notes into a separate .rst file and an
organizing top-level release notes page.

Create a draft version for the v0.2 release notes.

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>

doc/release_notes_0.2.rst

@@ -0,0 +1,42 @@
+.. _release_notes_0.2:
+
+ACRN v0.2 (Sep 2018) DRAFT
+##########################
+
+We are pleased to announce the release of Project ACRN version 0.2.
+
+ACRN is a flexible, lightweight reference hypervisor, built with
+real-time and safety-criticality in mind, optimized to streamline
+embedded development through an open source platform. Check out the
+:ref:`introduction` for more information.
+
+The project ACRN reference code can be found on GitHub in
+https://github.com/projectacrn.  It includes the ACRN hypervisor, the
+ACRN device model, and documentation.
+
+Version 0.2 new features
+************************
+
+
+Known Issues
+************
+
+.. comment
+   Use the syntax:
+
+   :acrn-issue:`663` - Black screen displayed after booting SOS/UOS
+     The ``weston`` display server, window manager, and compositor used by ACRN
+     (from Clear Linux) may not have been properly installed and started.
+     **Workaround** is described in ACRN GitHub issue :acrn-issue:`663`.
+
+
+Change Log
+**********
+
+These commits have been added to the acrn-hypervisor repo since the v0.1
+release in July 2018 (click on the CommitID link to see details):
+
+.. comment
+
+   This list is obtained from the command:
+   git log --pretty=format:'- :acrn-commit:`%h` %s' --after="2018-03-01"