Creates an instance of Encryptable.
An EventTemplate with optional tags and content.
Plaintext updates to be applied to the event content.
Here's an example which enables updating a private mute list:
const event = {kind: 10000, content: "", tags: []} // An event, only kind is required
const encryptable = new Encryptable(event, {content: JSON.stringify([["e", "bad word"]])})
const eventTemplate = await encryptable.reconcile(myEncryptFunction)
Represents an encryptable event with optional updates.