Add cloud id resolver interface

[smesterheide]

Summary

An application requires group ids that contain slashes and colons. Full reasoning given:

Cloud Ids consist of username and remote parts. Usernames can also be group names. Federated groups are required to have "prefixes" to distinguish them from regular groups. Here group ids (gids) are written as Uniform Resource Names (URNs) that have colons and slashes as part of the uri scheme. We need to allow these characters as part of group names. Keep in mind that groups in Nextcloud can already contain these characters anyway.

• Adds to: Add new share type federated_group and provider for VO app #52992
• Original PR: Add cloud id resolver interface #35732

Changes

• Instead of validating all possible cloud ids there is now a mechanism to register cloud id resolver

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[github-actions]

Hello there,
Thank you so much for taking the time and effort to create a pull request to our Nextcloud project.

We hope that the review process is going smooth and is helpful for you. We want to ensure your pull request is reviewed to your satisfaction. If you have a moment, our community management team would very much appreciate your feedback on your experience with this PR review process.

Your feedback is valuable to us as we continuously strive to improve our community developer experience. Please take a moment to complete our short survey by clicking on the following link: https://cloud.nextcloud.com/apps/forms/s/i9Ago4EQRZ7TWxjfmeEpPkf6

Thank you for contributing to Nextcloud and we hope to hear from you soon!

(If you believe you should not receive this message, you can add yourself to the blocklist.)

[icewind1991]

Looks good

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22

[susnux]

Thank you for the pull request!

Merging into our org to have proper CI and to apply suggested changes (author disabled changes on their branch).