Store Gateway should also implement the --disable-admin-operations CLI flag

[erikgb]

Is your proposal related to a problem?

As an admin, I want to enable the store gateway webapp, but I don't want to allow users to modify the backend store.

Describe the solution you'd like

This was reported as an issue on compactor and bucket web in #5390. I would like the same CLI option to be available for store gateway: --disable-admin-operations

Describe alternatives you've considered

A workaround could be to disable the store gateway webapp completely.

Additional context

[Naman-B-Parlecha]

Hey @yeya24 @GiedriusS , i want to pick this issue up could you guide me on it?

[yeya24]

You can do something similar to #6646.

@Naman-B-Parlecha