multiple namespaces for saved lists

[Klap-in]

request via the mail:

Also I have one suggestion for possible improvement:
Support for alias/wildcards in namespace where selections are saved (parameter save_namespace). For example to support entries like:

• user:%USER%:ebook
• %GROUP%:ebook

so every user or group have it’s own saved book collection.
(something like https://www.dokuwiki.org/acl#user_wildcards).

Ultimately it will be nice to have support for multiple saved lists: user specific, group specific and global (but that’s probably too much to ask).