Fix Argon2 descriptions

The threads option for the password_hash function does not define the maximum allowed number of CPU threads to be used by the hashing algorithm but the exact number of threads that is used.

Similarly the memory_cost option for the password_hash function does not define the maximum allowed memory to be used by the hashing algorithm, but the exact amount of memory that is used by the hashing table. The minimum value is 8 KiB per thread.

The time_cost option for the password_hash function does not define the allowed time in seconds, but the number of iterations for the hash function.

If the minimum values are understood, the minimum values are used instead.

Signed-off-by: MichaIng <micha@dietpi.com>