crypto-refresh: add support for Argon2 S2K (#1597)

In terms of API, this feature is backwards compatible, no breaking changes.
However, since a Wasm module is loaded for the Argon2 computation, browser apps
might need to make changes to their CSP policy in order to use the feature.

Newly introduced config fields:
- `config.s2kType` (defaulting to `enums.s2k.iterated`): s2k to use on
password-based encryption as well as private key encryption;
- `config.s2kArgon2Params` (defaulting to "uniformly safe settings" from Argon
RFC): parameters to use on encryption when `config.s2kType` is set to
`enums.s2k.argon2`;

src/message.js

@@ -18,6 +18,7 @@
 import * as stream from '@openpgp/web-stream-tools';
 import { armor, unarmor } from './encoding/armor';
 import KeyID from './type/keyid';
+import { Argon2OutOfMemoryError } from './type/s2k';
 import defaultConfig from './config';
 import crypto from './crypto';
 import enums from './enums';
@@ -183,6 +184,9 @@ export class Message {
             decryptedSessionKeyPackets.push(skeskPacket);
           } catch (err) {
             util.printDebugError(err);
+            if (err instanceof Argon2OutOfMemoryError) {
+              exception = err;
+            }
           }
         }));
       }));