Integration management for git projects

Introduced group-level integration management, allowing group owners and instance administrators to configure integrations for all projects within a group from a single place. This enhances security by allowing administrators to roll out integrations without sharing credentials with individual project owners. This feature is available for free on GitLab.com and self-managed instances running 13.6 and up. The post also outlines future considerations such as inheritance overviews, per-field inheritance, field masking, and inheritance locking. It also announces the deprecation of Service Templates in favor of this new group-level integration management.