tzdata: Add tzdata.zi to tzdata-core package

Additionally build and package tzdata.zi info file, as e.g. Systemd expects it
to be present.

[YOCTO #15172]

Signed-off-by: Simone Weiß <simone.p.weiss@posteo.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>