Support streaming AES CTR/GCM encryption/decryption

[xalanq]

If AES CTR/GCM mode can support the following streaming types, it would be very helpful to encrypt and decrypt large files without a lot of memory. Thanks!

export type Cipher = {
  update: (data: Uint8Array) => Uint8Array;
  final: () => Uint8Array;
};

export type Decipher = Cipher;

[paulmillr]

for now something like this can be built by users https://github.com/openpgpjs/openpgpjs/blob/b2bd8a0fdd12902484d65baa4ae4eb7f146fcd32/src/crypto/cipherMode/cfb.js#L357