find-dired: Add find-dired-with-command

find-dired: Add find-dired-with-command

Add a command that runs and sets up the find-dired buffer with an
arbitrary find command.  Also rewrite the existing find-dired commands
using it.

The set of commands possible with find-dired is limited; the new
command allows users to run the full set of commands, but also leaves
the responsibility to the user to construct the command manually.

* lisp/find-dired.el (find-command-history): New var.
(find-dired-with-command): New command.
(find-dired): Rewritten with new command.