Add chinese/bpmf-vsime: Bopomofo IVS reading selection tool

The tool is a local web page that highlights every Han character with more
than one Bopomofo reading, guesses the common ones from a bundled phrase
database, and produces plain text carrying the matching Ideographic
Variation Sequences.

The upstream distribution bundles a copy of BpmfZihiKaiStd-Regular.ttf for
the page to render with. Drop it and point the two @font-face rules at the
copy installed by x11-fonts/bpmf-zihikai instead, which is a run dependency.