Remove long deprecated gitrepo volume plugin from code base

[saad-ali]

What happened?

In SIG Storage Meeting today, @bswartz pointed out that gitrepo in-tree volume was deprecated a long time ago (see #60999) but the code is still around and may have vulnerabilities.

We should consider removing it.

What did you expect to happen?

It looks like completely removing the API/code would have been considered a backwards incompatible change which k8s avoids, and so only a deprecation notice was created and the code was left as is see #63445 (comment)

We have been able to get rid of other in-tree plugins by keeping the API and implementing "CSI migration" which enables the implementation to be removed and redirect to new CSI drivers. In this case there is no "CSI" migration -- instead the recommendation is to use emptyDir + initContainers.

To remove risk from the unmaintained code -- I suggest that we keep the API, but remove the implementation. (We did exactly this with Flocker, for example, see #111618)

How can we reproduce it (as minimally and precisely as possible)?

N/A

Anything else we need to know?

No response

Kubernetes version

1.30

Cloud provider

N/A

OS version

# On Linux:
$ cat /etc/os-release
# paste output here
$ uname -a
# paste output here

# On Windows:
C:\> wmic os get Caption, Version, BuildNumber, OSArchitecture
# paste output here

Install tools

Container runtime (CRI) and version (if applicable)

Related plugins (CNI, CSI, ...) and versions (if applicable)

[saad-ali]

/sig storage

[saad-ali]

/triage accepted

[saad-ali]

/assign @noctarius
Chris indicated on Slack he's interested in driving this.

[k8s-ci-robot]

@saad-ali: GitHub didn't allow me to assign the following users: noctarius.

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In response to this:

/assign @noctarius
Chris indicated on Slack he's interested in driving this.

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[saschagrunert]

duplicate of #125983