(U+FA3C): Add `<-denotational@usage' for A2-DJT-02517; apply new

(U+FA3C): Add `<-denotational@usage' for A2-DJT-02517; apply new
conventions for glyph granularity.
(U+4DB9): Add `sound@ja/on'; use `<-interchangeable' instead of
`->synonyms' for UU+5DE6; add some corresponding modern characters.
(A-GT-K02096): Moved to Ideograph-R017-Open-Box.el; unify A-BC-88C6.
(U-00021D09): New character.
(A-cgnU+21D12): New abstract node; unify A-C5-2876.
(U-00021D14): New character; use `<-denotational' for A-cgnU+21D12.
(M-07849): Add `<-denotational' for U-00021D14; delete `=>ucs' for
U-00021D12; unify IU+21D14.
(U-00021D12): Add `<-denotational' for U-00021D12; apply new
conventions for glyph granularity.
(U-00021D24): Apply new conventions for glyph granularity.
(A2-DJT-02517): New abstract node.