Retangle bundled font notices

Manrope 500/600 (static instances, version 4.504):
  Manrope-NOTICE.txt and Manrope-OFL.txt

Retangle CJK regional subsets (derived from Noto Sans CJK):
  NotoSansCJK-NOTICE.txt and NotoSansCJK-OFL.txt

These files accompany the font binaries in the game's runtime assets. The
notices retain their own licensing; they do not license Retangle as a whole.
Manrope 400 is retained with its notice and license in artwork/fonts for HTML
proposal tools; it is not bundled with the game.