distinguish between cached and uncached creds

p2p and multicast creds are not cached the same way that s3 and webdav
creds are. The difference is that p2p and multicast obtain the creds
themselves, as part of a process like pairing. So they're storing the
only extant copy of the creds. In s3 and webdav etc the creds are
provided by the cloud storage provider.

This is a fine difference, but I do think it's a reasonable difference.
If the user wants to prevent s3 and webdav etc creds from being stored
unencrypted on disk, they won't feel the same about p2p auth tokens
used for tor, or a multicast encryption key, or for that matter their
local ssh private key.

This commit was sponsored by Fernando Jimenez on Patreon.

Command/Multicast.hs

@@ -232,7 +232,7 @@ uftpKey = do
 	u <- getUUID
 	return $ KeyContainer $ "annex-" ++ fromUUID u
 #else
-uftpKey = KeyFile <$> cacheCredsFile "multicast"
+uftpKey = KeyFile <$> credsFile "multicast"
 #endif
 
 -- uftp needs a unique UID for each client and server, which