The basic `.get()` and `.set()` calls should be the same between
persistent key-value store (puter-kvstore) and in-memory cache (kv.js).
This commit wraps these methods to support the "shorthand" usage.
The data extension adds convenient access to the database and kvstore
via it's 'db' and 'kv' exports.
Example usage:
const { db, kv } = extensions.import('data');
await kv.set('some-key', 'some-value');
await db.write('INSERT INTO something (a, b) VALUES (1, 2)');
Daniel Salazar