Build a global (package,version) list for each type.
Keeping separate (per-origin) lists is misleading:
- Information is lost: we would need to keep track of all origins where
a given (package,version) is available from.
- That's actually not needed since we have references to the time-based
snapshots, and the server-side manifest consumer has everything to
decide which packages to keep for a tagged snapshot.
Therefore, drop per-origin lists; and keep a single list for each type
(binary, source).
Refs: #10748
Signed-off-by: Cyril Brulebois <cyril@debamax.com>