* Add POC of GitHub Webhook Delivery Forwarder
* multi-forwarder and ctrl-c existing and fix for non-woring http post
* Rename source files
* Extract signal handling into a dedicated source file
* Faster ctrl-c handling
* Enable automatic creation of repo hook on startup
* Add support for forwarding org hook deliveries
* Set hook secret on hook creation via envvar (HOOK_SECRET)
* Fix org hook support
* Fix HOOK_SECRET for consistency
* Refactor to prepare for custom log position provider
* Refactor to extract inmemory log position provider
* Add configmap-based log position provider
* Rename githubwebhookdeliveryforwarder to hookdeliveryforwarder
* Refactor to rename LogPositionProvider to Checkpointer and extract ConfigMap checkpointer into a dedicated pkg
* Refactor to extract logger initialization
* Add hookdeliveryforwarder README and bump go-github to unreleased ver