RFC - Remove dead code

Status:	unknown
Sponsored by:	no-one
Developed by:	no one
Expected for:	unknown
Bug number:	Bug 5324
Work in progress repository:	link(s) to currently published work on this RFC
Description:	The following routines are believed to be disused and of no particular use as standalone members of the C4 API. * C4::Koha::slashifyDate => superseded by C4::Dates * C4::AuthoritiesMarc::AUTHhtml2marc => Superseded by C4::Biblio::TransformHtmlToMarc

Dead Code