feat: add ocs route to get apps enabled for current user

[janepie]

Summary

Creates an OCS route to get a list of apps that are enabled for the currently logged-in user. No admin rights needed for this route.

(Needed for Context Agent to check the app's availability)

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)

[janepie]

Moved and adapted :) @julien-nc @provokateurin

[oleksandr-nc]

very nice

[janepie]

/backport to stable31

[susnux]

Dont forget to document the new API route https://github.com/nextcloud/documentation/blob/master/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_32.rst#added-apis-1

And because its backported:
https://github.com/nextcloud/documentation/blob/master/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_31.rst#added-apis

[janepie]

@susnux right, thanks for the reminder!

And because its backported: https://github.com/nextcloud/documentation/blob/master/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_31.rst#added-apis

Is this enough then or should I put it in both?

[susnux]

Hm good question, in theory 31 is enough

[nickvergessen]

No one is rechecking old documentation after updating their app. So I would say add it in both