Add Gitaly version to Admin Dashboard

Description

Add Gitaly version to Admin Dashboard

Proposal

Add Gitaly to the components list displayed on the Admin Dashboard. This will enable the Gitaly version to be easily determined without leaving the application

Documentation blurb

Overview

What is it?

A small addition to the admin dashboard to display the version of Gitaly running on the instance

Why should someone use this feature?

To determine the version of the Gitaly component without leaving the application

Use cases

Who is this for? Provide one or more use cases.

Administrators checking the version of the Gitaly component

Feature checklist

Make sure these are completed before closing the issue, with a link to the relevant commit.

• Feature assurance
• Documentation
• Added to features.yml