Webhooks are generated eagerly but have lazily set targets so that we can give the user a webhook URL to set in their config. go-neb (upstream & standalone) doesn't give a webhook URL until after the repositories are configured. Fixes #16
TODO: * Backend (needs research) * Webhook URL (probably proxy this)
Fixes #14
Using the RSS Bot as an example. Notably missing features: * Configuration (feeds) not retrieved * No actual configuration page
