copy/move --from-anywhere --to remote

Implementation was simple because it's equivilant to
--from=foo --to remote for each other remote, followed by
--to remote when there's a local copy.

(Or, in the edge case of --from-anywhere --to=here,
it's the same as --to=here.)

Note that, when the local repo does not have a copy,
fromToPerform gets it from a remote, sends it to the destination,
and drops the local copy. Another call to that for a second remote
will notice that the dest now has a copy, and simply drop from the
second remote, avoiding a second transfer.

Also note that, when numcopies doesn't allow dropping it from
everywhere, it will drop it from the cheapest remotes first
(maybe not ideal) up to more expensive remotes, and finally from the local
repo. So the local repo will generally end up holding a copy. Maybe not
ideal in all cases either, but it seems no worse to do that than to end up
with a copy undropped from a remote.

And I'm not entirely happy with the output, eg:

	copy bigfile (from r3...) ok
	copy bigfile ok

That makes sense if you think of the second line as being
the same as what is output by `git-annex copy bigfile --to bar`,
but it's less clear in this context. Maybe add "(from here...)"?
Also the --json output doesn't have a machine-readable field for
the "from" uuid, and maybe it should?

Sponsored-by: Dartmouth College's DANDI project

Command/Copy.hs

@@ -69,6 +69,7 @@ seek' o fto = startConcurrency (Command.Move.stages fto) $ do
 			FromOrToRemote (ToRemote _) -> Just True
 			ToHere -> Just False
 			FromRemoteToRemote _ _ -> Nothing
+			FromAnywhereToRemote _ -> Nothing
 		, usesLocationLog = True
 		}
 	keyaction = Command.Move.startKey fto Command.Move.RemoveNever
@@ -84,12 +85,13 @@ start o fto si file key = stopUnless shouldCopy $
 		| autoMode o = want <||> numCopiesCheck file key (<)
 		| otherwise = return True
 	want = case fto of
-		FromOrToRemote (ToRemote dest) ->
-			(Remote.uuid <$> getParsed dest) >>= checkwantsend
+		FromOrToRemote (ToRemote dest) -> checkwantsend dest
 		FromOrToRemote (FromRemote _) -> checkwantget
 		ToHere -> checkwantget
-		FromRemoteToRemote _ dest ->
-			(Remote.uuid <$> getParsed dest) >>= checkwantsend
-			
-	checkwantsend = wantGetBy False (Just key) (AssociatedFile (Just file))
+		FromRemoteToRemote _ dest -> checkwantsend dest
+		FromAnywhereToRemote dest -> checkwantsend dest
+
+	checkwantsend dest = 
+		(Remote.uuid <$> getParsed dest) >>=
+			wantGetBy False (Just key) (AssociatedFile (Just file))
 	checkwantget = wantGet False (Just key) (AssociatedFile (Just file))