Requires libsodium ≥ 1.0.9 to be present at compile time.
Thus, the following distributions will have support for at least
ARGON2i:
* rhel ≥ 7 (with EPEL enabled)
* Debian ≥ 9 (stretch)
* Ubuntu ≥ Bionic (18.04)
Fixes#4895
Extend NSData+Crypto to support PBKDF2 with SHA1 HMAC as dovecot
is using it since v2.3.0.
The format hashed passwords is {PBKDF2}$1$<salt>$<rounds>$<hashed value in hex>
The implementation of pkcs#5 PBKDF2 is taken from openbsd (with minor
adjustments) as OpenSSL and GnuTLS would require quite new versions to
support this hash.
Dovecot promotes the use of BLF-CRYPT as a hashing scheme [1].
However, as not all libc-crypt() implementations support this scheme,
use the implementation added in a previous commit.
Also, update the references to the dovecot implementation and a small
test case for testing the blowfish implementation.
[1] https://doc.dovecot.org/configuration_manual/authentication/password_schemes/Fixes#4958
