Support for Zoekt in GDK

What does this merge request do and why?

The Zoekt integration was recently added in gitlab!105049 (merged) . This makes it easy to configure Zoekt in your GDK environment.

Unlike Postgres, Zoekt, unfortunately, cannot share a single server for dev/test environment so we need to run separate servers for each. Then Zoekt is also composed of an indexserver and webserver which are separate so in total this means running 4 separate web servers in GDK.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.

Closes gitlab#389758 (closed)

Closes gitlab#389757 (closed)