feat(jdbc): add postQuery parameter

[lyogev]

No description provided.

[cyrillay]

Tested today on EMR and it worked like a charm, also with multiple queries on the same output. (I also didn't need to add ?allowMultiQueries=true on the JDBC connection URL)

- dataFrameName: df_item
  outputType: JDBC
  outputOptions:
    saveMode: Overwrite
    dbTable: item
    postQuery: CREATE INDEX index_item_key ON item(item_key(30));CREATE INDEX index_item_key_2 ON item(item_key_2(30));