Enable TenantSync and NamespaceSync to have separate source of truth for files

### Feature description

At the moment, TenantSync and NamespaceSync will sync all objects inside of Kestra based on the same source of truth. This works well for Kestra specific objects like Flows, Tests, Dashboards and Apps which are typically built directly inside of Kestra.

However, Namespace Files aren't typically modified inside of Kestra. Most use cases involve people wanting to take their already modified files (e.g. code) and sync them into Kestra so the workflow can use them. At the moment, these Sync tasks don't allow you to have all your Kestra specific objects have Kestra as the source of truth, and Namespace Files have GIT as the source of truth.

There's a few options I can imagine:
- `sourceOfTruth` is split into multiple properties. Kestra specific source of truth and Namespace source of truth
- Take it a step further and allow you to configure each objects source of truth (but at that point, you might as well use the specific tasks rather than modify this task.... however those only let you target specific namespaces, not entire tenants.