`cbind()` more diverse crosstables

Mono-by crosstables:

```r
ct1 = mtcars2 %>%
  crosstable(cyl, by=c(am),
             margin=c("row", "col"), total = FALSE)

ct2 = mtcars2 %>%
  crosstable(c(cyl), by=c(vs),
             margin=c("row", "col"), total = FALSE)

ct_bind_cols(ct1, ct2) %>%
  af()
```

More than 2 crosstables

```r
ct_bind_cols(ct1, ct1, ct1) %>%
  af()
```