feat: Multi-nerwork

[Khaaz]

This PR brings support to a multi network configuration.
This PR keeps backward compatibility, which means old config design should work as expected.

Networks should be added in two places:
Appended in config:

networks: [
  {
      "name": "network1",
      "authorizationGithub": "secret",
      "authorizationGitlab": "secret"
  },
]

Appended in webhooks:

"networks": []

This allow the same webhook to be in multiple network.
This allows to have a gitlab/github secret token per network.
It will fallback to the global authorisation if not specified

Closes #10