Display indicator for refetching mirrors

[sutterj]

Is your feature request related to a problem?

Currently, when the table is refetching, there is no indicator in the UI to show that this is happening. This could lead to confusion as to why the mirror that was just created/renamed/deleted isn't displayed correctly yet.

Describe the solution you'd like

There should be some indicator on the page to let the user know that the data in the table is being refetched.

Describe alternatives you've considered

No response

Additional context

No response