udev-event: add replace_whitespace param to udev_event_apply_format

If replace_whitespace is true, each substitution value has all its
whitespace removed/replaced by util_replace_whitespace (except the
SUBST_RESULT substitution - $result{} or %c{} - which handles spaces
itself as field separators).  All existing callers are updated to
pass false, so no functional change is made by this patch.

This is needed so the SYMLINK assignment can replace any spaces
introduced through variable substitution, becuase the SYMLINK value is
a space-separated list of symlinks to create.  Any variables that
contain spaces will thus unexpectedly change the symlink value from
a single symlink to multiple incorrectly-named symlinks.

This is used in the next patch, which enables the whitespace
replacement for SYMLINK variable substitution.