Check whether we can unify daps-xslt/docbook*-profiling.xsl files

[ghost]

We currently have separate profiling stylesheets for each DocBook minor version. However, they have very few differences between them.

We do need to keep at least one stylesheet for DocBook 4.x and one for 5.x. We may also want to keep the URNs for these stylesheets, as they are already established and should be kept stable.

DocBook 5.0 v/ 5.1 profiling stylesheet is completely unnecessary:

--- docbook50-profile.xsl	2021-06-10 12:24:28.098496200 +0200
+++ docbook51-profile.xsl	2021-06-10 12:24:28.098496200 +0200
@@ -17,8 +17,8 @@
                 version="1.0">
 
 <xsl:import href="base-profile.xsl"/>
-
+  
 <xsl:output method="xml"/>
-
+  
 </xsl:stylesheet>

DocBook 4.x profiling stylesheets have a version number difference, but it may be possible to catch that version number from the original document's DOCTYPE:

--- docbook41-profile.xsl	2021-06-10 12:24:28.098496200 +0200
+++ docbook44-profile.xsl	2021-06-10 12:24:28.098496200 +0200
@@ -24,7 +24,7 @@
   <xsl:copy-of select="/processing-instruction('xml-stylesheet')"/>
   <xsl:text>&#10;</xsl:text>
   <xsl:call-template name="create.db45.doctype">
-    <xsl:with-param name="version">4.1.2</xsl:with-param>
+    <xsl:with-param name="version">4.4</xsl:with-param>
   </xsl:call-template>
 </xsl:template>