Github pages assumes that links to files using relative
names point to the same location so this should work both
when accessing through the github browser and mcuboot.com
Signed-off-by: Fabio Utzig <utzig@apache.org>
Move the release notes document into the docs directory, and convert to
Markdown so that it can be rendered on the project's website.
Signed-off-by: David Brown <david.brown@linaro.org>