Add a legacy zip store for writing backwards-compatible kra files

Use the Quazip store for reading and writing 64 bits zip files,
the Legacy store for writing 32 bits zip files. It's still not
ideal, having two zip implementations (and a third one hidden
inside Qt), but this gives maximal compatibility. Vectors and
colorize masks load again as well.

BUG:407601
BUG:407630
CCBUG:407537