template: Added an XSL template to support glossary variable permalinks

Fixes [YOCTO #5772]

With this template, all that is necessary to trigger permalink
generation for variable entries in a manual's glossary  is to
update the customization layer to include the gloss-permalinks.xsl
file.

(From yocto-docs rev: aebe1a727be7921fe9bc26101b670d5fdc1670e4)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/template/gloss-permalinks.xsl

@@ -0,0 +1,14 @@
+<xsl:stylesheet version="1.0"
+  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+  xmlns:d="http://docbook.org/ns/docbook"
+  xmlns="http://www.w3.org/1999/xhtml">
+
+  <xsl:template match="glossentry/glossterm">
+    <xsl:apply-imports/>
+    <xsl:if test="$generate.permalink != 0">
+      <xsl:call-template name="permalink">
+        <xsl:with-param name="node" select=".."/>
+      </xsl:call-template>
+    </xsl:if>
+  </xsl:template>
+</xsl:stylesheet>