Add admin API endpoint to delete or purge images from pict-rs

[Nothing4You]

Requirements

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• Is this a backend issue? Use the lemmy-ui repo for UI / frontend issues.
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Is your proposal related to a problem?

Admins currently have to resort to calling the pict-rs API directly to purge images or delete aliases.

Describe the solution you'd like.

The simplest solution for the time being would be to provide an API that allows entering arbitrary pict-rs links and have Lemmy translate this into pict-rs delete/purge calls.
Both deletion and purge should be available as separate options, as it may be desirable to use them in different situations.

For the UI-side, this could be as simple as having a text input with a submit button.

Describe alternatives you've considered.

Make pict-rs directly accessible to all site admins.

Additional context

No response

[dessalines]

Oh I guess when we removed delete tokens, we removed this ability.

We already have the ListAllMedia endpoint for admins, so whats needed is a DeleteImage that works for admins.

[Nothing4You]

yeah, and also an explicit purge endpoint would be good for certain types of media where you want to be sure that there are no other aliases keeping it alive

[Nutomic]

Purge can be a boolean parameter for the admin delete endpoint.

[dessalines]

There currently isn't one, only a delete_image for your own images, and its in the wrong place. I'll fix this now.