staging: most: core: separate property showing links
Currently an AIM has the following properties available to manage links:
- write-only "remove_link" used to remove a link from a list
- read/write "add_link" used to add a link to a list and display them
This patch transfers the read functionality of "add_link" to the new
read-only property "links" to build consistent set of properties to control
the list of links.