doc: Update links within imported wiki content

This patch covers two changes:

- Links that refer to GitHub are updated to point to the
  relevant content on trustedfirmware.org

- Internal links between documents have been updated,
  with the required .rst suffix being added or due
  to a change in the relative locations of the files.

Change-Id: Ibf87da7d2ece726d1c94a9b33a2bbc3129de7779
Signed-off-by: Joel Hutton <Joel.Hutton@Arm.com>
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/frequently-asked-questions.rst b/docs/frequently-asked-questions.rst
index 3b14446..c0cbc0d 100644
--- a/docs/frequently-asked-questions.rst
+++ b/docs/frequently-asked-questions.rst
@@ -84,5 +84,5 @@
 infrastructure and can be safely ignored. Those who are curious can see the
 documentation for `this Jenkins plugin`_ for more details.
 
-.. _release information: release-information
+.. _release information: release-information.rst
 .. _this Jenkins plugin: https://wiki.jenkins-ci.org/display/JENKINS/GitHub+pull+request+builder+plugin