Move release docs to release/ dir

Created a release/ dir and moved release docs to it.
Renamed release docs with a - (this is the convention used in
the other docs).
Fixed the link release-notes.md

Change-Id: I565ccb38f55dbdc4fcf84a743bd7928c826dda30
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/release_notes.md b/release/release-notes.md
similarity index 98%
rename from release_notes.md
rename to release/release-notes.md
index 418e999..e935014 100644
--- a/release_notes.md
+++ b/release/release-notes.md
@@ -5,7 +5,7 @@
 for completeness.
 
 Read more about the release process here:
-https://github.com/openbmc/docs/blob/master/release_process.md
+https://github.com/openbmc/docs/blob/master/release/release-process.md
 
 For information on how to checkout a particular branch or tag, see:
 https://github.com/openbmc/openbmc/wiki/Releases
diff --git a/release_process.md b/release/release-process.md
similarity index 100%
rename from release_process.md
rename to release/release-process.md