project: implement a github webhook filter using azure functions

[ssbarnea]

We want to fine-tune github webhook events from our repositories and resend filtered events further to slack, matrix, notifico.

As we already be using Azure, Azure functions would make sense to make use of https://learn.microsoft.com/en-us/training/modules/monitor-github-events-with-a-function-triggered-by-a-webhook/ to implement these as we would not have to maintain the system ourselves.

Configuration for this should be stored inside devtools repository, where we already have the list of repositories we own.

• implement the filtering function as POC, configure it for this repository with outgoing hook to our slack channel
• add a list of outgoing hooks (encrypted using an ansible vault) to this repo
• add GHA pipeline to deploy the changes when the file is modified