Cannot register table to represent multiple parquet files in S3 bucket

**Describe the bug**
This works:

```sql
CREATE EXTERNAL TABLE yellow_2019_01 STORED AS PARQUET LOCATION "s3://ossb-nyctaxi/yellow/2019/yellow_tripdata_2019-01.parquet";
```

This does not work:

```sql
CREATE EXTERNAL TABLE yellow_2019 STORED AS PARQUET LOCATION "s3://ossb-nyctaxi/yellow/2019";
```

Fails with:

```
ObjectStore(NotFound { path: "yellow/2019", source: Error { retries: 0, message: "No Body", source: Some(reqwest::Error { kind: Status(404), url: Url { scheme: "https", cannot_be_a_base: false, username: "", password: None, host: Some(Domain("s3.us-east-2.amazonaws.com")), port: None, path: "/ossb-nyctaxi/yellow/2019", query: None, fragment: None } }) } }
```

**To Reproduce**
As described.

**Expected behavior**
Should be able to register a directory containing parquet files.

**Additional context**
Possibly related to https://github.com/apache/arrow-datafusion/issues/1736

Start with CREATE EXTERNAL TABLE handling for S3 locations and reproduce the two SQL statements from the issue. Trace how a directory path is resolved versus a single parquet object; done means a directory containing parquet files can be registered as one external table.

Written by the indexing model from the issue text.