Add custom webhooks

[Ceddicedced]

Describe the solution you'd like

It would be nice instead of just having the discord functionality, setting a custom webhook e.g. to send messages that would normally be sent to discord can now be sent to ntfy.

Feature Report Checklist

• I am willing to implement this feature --- maybe

[thijsvanloef]

Hi @Ceddicedced Could you give some examples on what kind of messages you would like?

[Ceddicedced]

Basically everything that the discord webhook covers. So Start / Stop / Player Joins etc. But instead of having the custom discord fields only simple messages are provided via curl -d "MESSAGE" webhook.example.com