Sha2-512 Packages

how to import: ``` const sha2_512 = require('simple-js-sha2-512') ``` hashing: ``` sha2_512('hello') // 9b71d224bd62f3785d96d46ad3ea3d73319bfbc2890caadae2dff72519673ca72323c3d99ba5c11d7c7acc6e14b8c5da0c4663475c2e5c3adef46f73bcdec043 ```

simple js sha2 implementation (includes 224bit, 256bit, 384bit, 512bit)