Added generic types for event payloads

[mdw19873]

What does this PR do?

Adds generic typings to all event triggering methods. This will allow developers to define payload interfaces and enforce them at compile time. This should be able to drop in without causing anyone issues.

Checklist

• All new functionality has tests.
• All tests are passing.
• New or changed API methods have been documented.
• npm run format has been run

CHANGELOG

• [CHANGED] Updated TypeScript typings to add T = any for the data argument on the trigger(), triggerBatch(), and sendToUser() methods. As well as the BatchEvent interface.