* Webhook: Add support for message edit and delete
* Webhook: remove global functions
* Webhook: move package Webhook into api/
* Webhook: Moved (unused in API) data struct to package webhook
Co-authored-by: diamondburned <datutbrus@gmail.com>
* API: separate token-based and bot-based interactions with webhooks
* API: move writeMultipart to internal/multipartutil
* Multipartutil: fix double filetype-suffix