Geo: Add correlation ID to Geo::RequestService requests

What / Why

Because GitLab Geo is composed of multiple services (at least one primary and one secondary site), relevant logs need to have a common identifier to allow debugging across services.

Proposal

Because GitLab Geo is composed of multiple services (at least one primary and one secondary site), relevant logs need to have a common identifier to allow debugging across services. For example, when a Git push occurs, the correlation ID should propagate across sites.

Implementation

TBD