Features:
+* sd-bus: when connecting to some dbus server socker, set originating AF_UNIX
+ socket name in abstract namespace to include "description" string, and pick
+ it up from there in sd_bus_creds logic. i.e. we can use the socket peer
+ address as conduit for some minimal connection metainfo, and use it to
+ restore the "description" logic that kdbus used to have.
+
* teach LoadCredential= the ability to load all files from a specified dir as
individual creds