ctdb-scripts: Update important installed files to use build-time defaults

ctdb-scripts: Update important installed files to use build-time defaults

In this case: ctdbd_wrapper, onnode, ctdb_diagnostics, ctdb.sudoers.
Set sensible defaults from configure options.

Update documentation to match, trying to fix up anything that has been
missed before.

The onnode unit tests need a symlink to the functions file.
The simple integration tests need to set CTDB_BASE and also
need symlinks to functions/nodes.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Jose A. Rivera <jarrpa@samba.org>
Reviewed-by: Michael Adam <obnox@samba.org>
fixup

Signed-off-by: Martin Schwenke <martin@meltin.net>