[Security] Use a CSPRNG for salts, tokens, and RNG seeding

Password salts and activation tokens were generated with the global SFMT
RNG, which was seeded from a 32-bit timestamp, making registration
salts and activation tokens predictable. The game RNG used the same
timestamp seed across restarts.

Add CryptoUtil backed by OpenSSL RAND_bytes and use it for salt/token
generation and to seed RNG_SFMT with a 64-bit CSPRNG value in both the
client and server. Link libcockatrice_utility against OpenSSL::Crypto.

Took 30 seconds

Took 25 minutes

.ci/Arch/Dockerfile

@@ -8,6 +8,7 @@ RUN pacman --sync --refresh --sysupgrade --needed --noconfirm \
         gtest \
         mariadb-libs \
         ninja \
+        openssl \
         protobuf \
         qt6-base \
         qt6-declarative \