Review default otterdog configuration

We need to review the default configuration that should be used to roll out the tool to organizations.

The current version used for development is available at: https://gitlab.eclipse.org/eclipsefdn/security/otterdog/-/blob/main/default-org.libsonnet

Changes can be requested via a merge request.

After we have agreed on a default configuration, we should upload it to a public github repo so that it can be referenced by jsonnet-bundler.