[otrs] Charset decode

We have that future in LDAP customer external backend. But very need when use DB external backend for customers. # SourceCharset => 'utf-8' # DestCharset => 'iso-8859-1' For example main OTRS interface use UTF-8 and database backend use Windows-1251 charset. We need to decode charset on fly! Thank's Russian users, RombNet ISP, Evgeniy Gejnak.