series: rename any_applied() to any_committed()

The any_applied() function checks whether any patch in a series has been
committed.  Rename the function to make this clear.

The term "applied" will be used for patches that have received a
"Thanks, applied" message from a maintainer in the future, so don't
overload the meaning.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
scan: add 'applied-by' metadata to series

Store the name/email of the person who sent a "Thanks, applied" reply.
This is useful for detecting patch series that have already been merged
by subsystem maintainers but are not yet committed in the main
repository.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
query: add status:applied

Now that patch series have 'applied-by' metadata we can query them.
Also update the status:unapplied query expression to exclude patches
that have "Thanks, applied" replies.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>