ownCloud -> Nextcloud

PSR-4 for the Theming app

fix background id selector for the first run wizard

Fix undefined OfflineUser::composeAndStoreDisplayName()

Prevent setting email and triggering events at login time (#25553)

add info about the Nextcloud VM

Add L10N support

It's production ready now.

fix capitalization of text in users management

apply theme to the firstrunwizard

libxml - compare against loaded version

Colorize checkboxes depending on theming color

New LDAPProvider for user_ldap

Add a simple Admin UI to manage systemtags

* if the compiled in version is older than the loaded version Nextcloud doesn't work
* uses the loaded libxml version to check against

fixes #205

Support subdir in the OCS v2 endpoint

Don't try to load previews when we know there is none