BibConvert: Add XSLT/XML files for Inspire to CDS

* Includes the XSLT stylesheet for conversion of MARCXML
  from the Inspire format to CDS. They were originally available
  on the INSPIRE tWiki page SystemOperationsCDSIngestion
  authored by Jan Aage Lavik <jan.age.lavik@cern.ch> and
  maintained by Rasmus Thogersen <doodlingwhale@gmail.com>.

  They've been included here for version control reasons.
  inspire2cds.xsl is included with dependencies (XML files).

* New files included in Makefile, installs to bibconvert/config
  folder.

* XSL file preserves DOI, hyphens removed from CDS labels in
  experiments XML file, author name initials converted to spaces
  instead of being removed.

Co-authored-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Co-authored-by: Rasmus Thogersen <doodlingwhale@gmail.com>