EVP_MD_CTX_set_pkey_ctx() is fairly new openssl function, and not
existing in many alternative. Use EVP_MD_CTX_reset() which is slightly
more heavy but more portable. Add also signature buffer lengths to
work with RSA.
- 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