Add support for SHA3

[rkeene]

SHA3 is becoming more popular and supported by NodeJS, support for it should be added here as well. The popular package "jsSHA" supports this in a relatively easy to wrap way:

class browserSHA3_256 {
    #obj;

    constructor(hmacKey = undefined) {
        if (hmacKey === undefined) {
            this.#obj = new jssha("SHA3-256", "ARRAYBUFFER");
        } else {
            if (!(hmacKey instanceof Uint8Array)) {
                throw(new Error('only support Uint8Array for HMAC Key'));
            }

            this.#obj = new jssha("SHA3-256", "ARRAYBUFFER", {
                hmacKey: {
                    format: "UINT8ARRAY",
                    value: hmacKey
                }
            });
        }
    }

    update(data, options = undefined) {
        if (options !== undefined) {
            throw(new Error('options for "update" not supported'));
        }

        if (!(data instanceof ArrayBuffer)) {
            data = bufferToArrayBuffer(Buffer.from(data));
        }

        this.#obj.update(data);

        return(this);
    }

    digest(encoding = undefined) {
        let retval;
        switch (encoding) {
            case 'hex':
                retval = this.#obj.getHash("HEX");
                break;
            case undefined:
                retval = Buffer.from(this.#obj.getHash("ARRAYBUFFER"));
                break;
            default:
                throw(new Error(`unsupported encoding "${encoding}"`));
        }

        return(retval);
    }
}