Workspaces Cluster Agents Admin Settings UI

MR: see Implementation Plan below for MR breakdown

Description

We would need to roll out a workspace submenu under the admin area in keeping with the "instance-level" feel.

Designs can be found in: New UI in the admin section to support mapping ... (#513370 - closed)

Acceptance criteria

• UI is implemented as per designs with the exception of the search bar. In this current iteration, we will be implementing pagination instead.

Implementation Plan

	Step	MR
1	UI skeleton: this includes adding the GitLab Agents Availability setting in the Admin UI and creating the table based on design using mock data. This also involves adding a wip feature flag workspaces_agents_availability_admin, which this feature will be hidden behind until all steps are completed.	Add workspaces agent availability to admin sett... (!191120 - merged)
2	Pass organization ID to Vue app along with additional UI requirements	Workspaces Agents Admin UI: pass organization I... (!192594 - merged)
3	Implement query: query agents to render the table. Pagination will be handled in this step.	Implement Workspaces Agent Availability query a... (!192470 - merged)
4	Implement mutation: create/delete mapping on availability toggle.	Implement organization cluster agents mapping m... (!193134 - merged)
5	Apply copy feedback from Technical Writing	Update copy based on TW feedback (!194266 - merged)