[SPARK-16101][SQL] Refactoring CSV write path to be consistent with JSON data source

## What changes were proposed in this pull request?

This PR refactors CSV write path to be consistent with JSON data source.

This PR makes the methods in classes have consistent arguments with JSON ones.
  - `UnivocityGenerator` and `JacksonGenerator`

    ``` scala
    private[csv] class UnivocityGenerator(
        schema: StructType,
        writer: Writer,
        options: CSVOptions = new CSVOptions(Map.empty[String, String])) {
    ...

    def write ...
    def close ...
    def flush ...
    ```

    ``` scala
    private[sql] class JacksonGenerator(
       schema: StructType,
       writer: Writer,
       options: JSONOptions = new JSONOptions(Map.empty[String, String])) {
    ...

    def write ...
    def close ...
    def flush ...
    ```

- This PR also makes the classes put in together in a consistent manner with JSON.
  - `CsvFileFormat`

    ``` scala
    CsvFileFormat
    CsvOutputWriter
    ```

  - `JsonFileFormat`

    ``` scala
    JsonFileFormat
    JsonOutputWriter
    ```

## How was this patch tested?

Existing tests should cover this.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #16496 from HyukjinKwon/SPARK-16101-write.