Log more event types

[domwhewell-sage]

Currently the webhook only accepts these events

• Clicked Link
• Submitted Data
• Email Opened

Anything else causes a panic (I think the "Email Sent" event caused the panic in #2)

I would like to see it capable of accepting the "Email Sent" event and maybe others. Having all these events could cause it to send alot more notifications out so it would also be nice to have what types of events to ingest be configurable in the config.yaml file, Like:

# Enables notifications for each of the webhook events https://docs.getgophish.com/user-guide/documentation/webhooks. Options are `email_error`, `email_sent`, `email_opened`, `clicked_link`, `submitted_data` and `email_reported`.
events:
  - email_error
  - email_sent
  - email_opened
  - clicked_link
  - submitted_data
  - email_reported

If I have time I will submit a PR for this