Robust linking between Sessions and GitLab domain items
## Problem
With https://gitlab.com/gitlab-org/gitlab/-/work_items/572585 we're showing Sessions within the Work Items and MRs. However, creating the link is not an automatic process yet and there is also no way to link sessions into further GitLab Domain items such as Pipelines or Epics.
## Desired Outcome
A scalable and robust solution that automates the creation of a link between Session and GitLab Domain items where a session is initiated from or which get changed through a session.
epic