mei v3 to v4 xslt should generate<appInfo> entry

[bwbohl]

The mei30To40.xsl does a very good job in adding a <change> corresponding to its own execution, thus documenting it has been executed on the file. Nevertheless this change points from its @resp to a @xml:id that cannot be resolved against the resulting document.
Ideally this would be fixed by also introducing an entry in the <appInfo> referencing the script, potentially identifying the processor or transformation engine.

[bwbohl]

alternatively it could point to this repo and the XSLT in the respective release version

[bwbohl]

opinions?

[musicEnfanthen]

@bwbohl Can we use the same approach as in the mei40to50 XSLT here?