Move sources and sinks under the project scope

[leoll2]

Currently, the Geti Tune API allows you to configure sources and sinks globally, and reuse them across multiple projects. While very flexible, this approach is not well aligned with the current UX design, nor with the API of other Geti projects (namely Geti Prompt).

Therefore, it was decided to change the current approach and move the source and sink configuration into the project scope. This implifies the following API changes:

• For source endpoints, the prefix changes from /api/sources to /api/projects/{id}/sources
• For sink endpoints, the prefix changes from /api/sinks to /api/projects/{id}/sinks

At the database level, the tables sources and sinks should be extended with a new field project_id.

UI should be adjusted accordingly to call the new endpoints. Except for the scope change, the API semantics is unchanged.