arrow

ARROW-7045: [R] Preserve factor in Parquet roundtrip

The ability to preserve categorical values was introduced in https://github.com/apache/arrow/pull/5077 as the convention of storing a special `ARROW:schema` key in the metadata. To invoke this, we need to call `ArrowWriterProperties::store_schema()`.

The R binding is already ready for this, but calls `store_schema()` only conditionally and uses `parquet___default_arrow_writer_properties()` by default. Though I don't see the motivation to implement as such in #5451, considering [the Python binding always calls `store_schema()`](https://github.com/apache/arrow/blob/dbe708c7527a4aa6b63df7722cd57db4e0bd2dc7/python/pyarrow/_parquet.pyx#L1269), I guess the R code can do the same.

Closes #6135 from yutannihilation/ARROW-7045_preserve_factor_in_parquet and squashes the following commits:

9227e7e49 <Hiroaki Yutani> Fix test
4d8bb4697 <Hiroaki Yutani> Remove default_arrow_writer_properties()
dfd08cbd8 <Hiroaki Yutani> Add failing tests

Authored-by: Hiroaki Yutani <yutani.ini@gmail.com>
Signed-off-by: Neal Richardson <neal.p.richardson@gmail.com>