Implement Support for the rest of the Discord Webhook API

[nopjmp]

I would like to implement the rest of the API in a simple way. Possibly in another class to avoid loading unnecessary classes.

https://discordapp.com/developers/docs/resources/webhook#execute-webhook

• [x] Basic Messages
• [x] Communicate with JSON
• [ ] Communicate with form encoding
• [ ] Upload files
• [x] TTS
• [x] Basic Embed Support

[bennetgallein]

See my pull request, I implemented both.