arrow

ARROW-13371 [R] binding for make_struct -> StructArray$create()

This PR implements a binding for the `make_struct` compute function. This function was already being called in the translation for `case_when()` but didn't have a binding of its own. Because you can do this in dplyr too (create a nested data frame), I mapped `tibble()` and `data.frame()` since it can be tested using `compare_dplyr_binding()`. `StructArray$create()` is a nested call and is probably not that useful of a translation for dplyr users (I'd never think to use it).

Basically, you can now do this:

``` r
library(arrow, warn.conflicts = FALSE)
library(dplyr, warn.conflicts = FALSE)

df <- RecordBatch$create(a = 1, b = "two")
df %>%
  mutate(df_col = tibble(a, b)) %>%
  collect()
#> # A tibble: 1 × 3
#>       a b     df_col$a $b
#>   <dbl> <chr>    <dbl> <chr>
#> 1     1 two          1 two
```

Something I didn't do but could is add all the arguments of `tibble()` and `data.frame()` that aren't supported (e.g., `stringsAsFactors`). It seems like this is done for other translations but I just wanted to check!

Closes #11690 from paleolimbot/r-make-struct

Authored-by: Dewey Dunnington <dewey@fishandwhistle.net>
Signed-off-by: Jonathan Keane <jkeane@gmail.com>