Add new authentication header for calls made by agents to GitLab

MR: Add agentwinfo (!2590 - merged)

Description

As part of this epic, we are looking at introducing different type of agents. Right now, all calls made to GitLab have the header Gitlab-Agentk-Api-Request for authentication. We should add a new header Gitlab-Agent-Api-Request. to make it generic for all the different types of agents.

Acceptance criteria

Implementation plan

TODO

Edited by Vishal Tak