Upgrade to Nextcloud 33

Front-end changes

The global md5 implementation is removed. It was deprecated since Nextcloud 20 and not used by Nextcloud anymore. If you still need a md5 implementation you can just use some external package like crypto-browserify.
The OC.SystemTags api was removed. If you need to get the list of system tags, check this merge request for how to fetch the tags directly.
The OCA.Sharing.ExternalLinkActions API was deprecated in Nextcloud 23 and is now removed. It was replaced with OCA.Sharing.ExternalShareAction which now have a proper API by using registerSidebarAction from @nextcloud/sharing instead.

In this release support for PHP 8.1 was removed. Follow the steps below to make your app compatible.

If appinfo/info.xml has a dependency specification for PHP, increase the min-version to 8.2.

<dependencies>
  <php min-version="8.2" max-version="8.4" />
  <nextcloud min-version="31" max-version="33" />
</dependencies>

If your app has a composer.json and the file contains the PHP restrictions from info.xml, adjust it as well.

{
  "require": {
    "php": ">=8.2 <=8.4"
  }
}

If you have continuous integration set up, remove PHP 8.1 from the matrices of tests and linters.

The \OCP\BackgroundJob\IJob::execute method was deprecated since Nextcloud 25 and was now removed. Instead use the IJob::start method, available since Nextcloud 25.
The \OCP\Search\PagedProvider, \OCP\Search\Provider and \OCP\Search\Result classes were deprecated since Nextcloud 20 and were now removed. Instead use \OCP\Search\SearchResult and \OCP\Search\IProvider, available since Nextcloud 20.