Rework connection local variables

Rework connection local variables

For connection local variables interface, `class' is renamed
to `profile'.  All arguments `criteria' are a plist now.

* doc/lispref/variables.texi (Connection Local Variables):
Rewrite.

* lisp/files-x.el (connection-local-profile-alist): Rename
from `connection-local-class-alist'.  Adapt docstring.
(connection-local-criteria-alist): Adapt docstring.
(connection-local-normalize-criteria): New defun.
(connection-local-get-profiles): Rename from
`connection-local-get-classes'.  Rewrite.
(connection-local-set-profiles): Rename from
`connection-local-set-classes'.  Rewrite.
(connection-local-get-profile-variables): Rename from
`connection-local-get-class-variables'.  Rewrite.
(connection-local-set-profile-variables): Rename from
`connection-local-set-class-variables'.  Rewrite.
(hack-connection-local-variables)
(hack-connection-local-variables-apply)): Rewrite.
(with-connection-local-profiles): Rename from
`ith-connection-local-classes'.  Rewrite.

* lisp/net/tramp.el (tramp-set-connection-local-variables):
Compute criteria.

* lisp/net/tramp-cmds.el (tramp-bug):
Use `connection-local-profile-alist'.

* test/lisp/files-x-tests.el (files-x-test--variables1)
(files-x-test--variables2, files-x-test--variables3)
(files-x-test--variables4, files-x-test--criteria1)
(files-x-test--criteria2): Make them a defconst.
(files-x-test--application)
(files-x-test--another-application, files-x-test--protocol)
(files-x-test--user, files-x-test--machine): New defconst.
(files-x-test--criteria): New defvar.
(files-x-test--criteria3): Remove.
(files-x-test-connection-local-set-profile-variables):
Rename from `files-x-test-connection-local-set-class-variables'.
Rewrite.
(files-x-test-connection-local-set-profiles): Rename from
`files-x-test-connection-local-set-classes'.  Rewrite.
(files-x-test-hack-connection-local-variables-apply)  Rewrite.
(files-x-test-with-connection-local-profiles): Rename from
`files-x-test-with-connection-local-classes'.  Rewrite.