Rename setups and add provider reauthentication

server/src/files.rs

@@ -1,7 +1,7 @@
-//! Reading and changing files on the machine a setup names.
+//! Reading and changing files on a configured machine.
 //!
 //! Every operation here is one small POSIX shell script handed to `Transport`,
-//! the way `setups::discover` and `import::list` already ask a machine a
+//! the way `machines::discover` and `import::list` already ask a machine a
 //! question. That is what makes the local and the ssh case one implementation:
 //! a second one written against `std::fs` would be the one that gets tested,
 //! and the remote half -- the ordering of entries, what a symlink reports, how