`OCA.Files.Sidebar` API was removed in Nextcloud 33

[susnux]

This app still uses the OCA.Files.Sidebar API to register a sidebar tab.
But this API was removed in Nextcloud 33 as it still used the legacy FileInfo API.

With Nextcloud 33+ there is a new Node based api available (from @nextcloud/files package) to register sidebar tabs based on web components, see also:
https://nextcloud-libraries.github.io/nextcloud-files/functions/index.registerSidebarTab.html

You can take some inspiration from the files_versions app which is also Vue 3 based:
nextcloud/server@493c371#diff-c97cbd0e12cc4e01fb6c48f8338c3b53971d5c49a8a607726bb91258ea266c92

cc @lukasdotcom @julien-nc

[julien-nc]

@susnux Thanks for notifying us.

Could you review #355?