Export encodeTime to allow encoding of a MAX token when querying a list

[evanderkoogh]

When you want to query a list of items in a Durable Object you need to create a token for the MAX value.

Such as:

const encodedNow = encodeTime(Date.now())
    const taskList = await this.storage.list<AllTasks>({
      prefix: '$$_tasks::',
      end: `$$_tasks::${encodedNow}}`,
    })