This moves and isolates the tar code to tar.c. And the actual
file extraction to disk is moved to extract.c.
A new API is introduced and used for v2 file extraction. This
essentially moves and isolates the apk_sign_ctx_* beast into
extract_v2.c and offers a saner interface to handling packages.
A place holder is added for v3 extraction.
- basic digesting and signing apis (subject still to fine tuning)
- update digest code, and adb signing for the thin wrapping layer
- old v1 package and database handling not updated
- default mkpkg file hash to sha256
ref #10744
Timo Teräs