tex-bxjscls{,-doc}: Add version 2.5

From Atsushi Toyokura in pkgsrc-wip

This package provides an extended version of the Japanese
document class collection provided by jsclasses. While the
original version supports only pLaTeX and upLaTeX, the extended
version also supports pdfLaTeX, XeLaTeX and LuaLaTeX, with the
aid of suitable packages that provide capability of Japanese
typesetting.

(markd)