Associate cache to account that redeemed the code

[trs]

In v1.0, shift codes are cached all together instead of with the account that redeemed them. This is a regression from v0.0.

When loading the code cache during redeem use the session account ID as a key when adding a cached code.

Something along these lines should do it:

const cache = await loadContents<CacheStore>(CACHE_FILE, {});
if (!cache[acc.id]) {
 cache[acc.id] = [];
}

...

cache[acc.id].push(code);
await storeContents(CACHE_FILE, cache);

Should we store cached codes in a different file instead of in the same?