Make project context header optional in all but create endpoints

[eleftherioszisis]

• Create endpoints require a mandatory vlab/proj id pair as before
• In all other endpoints:
  • If a user passes vlab/proj id pair in the header things will work as they used to constraining the queries into that project.
  • If a user passes just their token, then the user_project_ids in the token will be used in the queries.
  • vlab/proj id context has precedence over user_project_ids

Note: Using the token is more permissive because the query will check the authorized_project_id of the entities against all authorized user project ids.

[jdcourcol]

Create endpoints require a mandatory vlab/proj id pair as before

@eleftherioszisis why not just the project_id ?