Support retrieving available SKUs via /applications/{application.id}/skus

[rainbowdashlabs]

General Troubleshooting

• [x] I have checked for similar issues on the Issue-tracker.
• [x] I have updated to the latest JDA version
• [x] I have checked the branches or the maintainers' PRs for upcoming features.

Feature Request

There is an endpoint that allows retrieving the available SKUs an application has to offer. The endpoint is /applications/{application.id}/skus https://discord.com/developers/docs/resources/sku#list-skus It simply returns a list of skus.

This possibility was implemented once already in #2667 but then removed during review without providing a reason for it to be removed.

Currently JDA does not support to retrieve available skus. Only entitlements can be retrieved. However for an entitlement to exist there needs to be a purchase of said sku. So you cant even know available skus, when they didnt get purchased yet. It is also inefficient to retrieve entitlements, when you are just interested into the existing skus.

Example Use-Case

Example uses cases would be to:

• list available skus
• perform bootstrapping of values in a config for example and validating that required skus are actually available on this application
• Allow auto completion when granting skus via a command