Added the doc-baseuri param to the stylesheet used for

Added the doc-baseuri param to the stylesheet used for
automatically adding hyperlinks in generated doc for stylesheet
params and in release-notes output.
For output of the param doc, doc-baseuri is set to "../" (relative
path so links point to local files).
For release-note output, doc-baseuri is set to the http: url for
the current version of the docbook-xsl docs (instead of to local
files); reason being that when installed from a downstream
package, the release notes can't point to local files because the
release notes are often installed in a separate place for the docs.