Rostdav 0.5.0

Added

• rostdav admin import-nextcloud <data-dir>: imports a Nextcloud data directory (ADR 0011). Every user's files with names and modification times, and the versions Nextcloud kept (files_versions), into the Rostdav user of the same name (--map NC=USER to rename, --only to pick). The directory is only read, so Nextcloud can keep running; the command can be repeated, --update replaces files that changed (the old content becomes a version), --dry-run writes nothing. Not imported, and listed in the output: the trash, group folders, external storage, shares, favorites and files encrypted by Nextcloud.