`Select outfile into` currently only supports to export data with CSV format.
This patch extends the feature to supports parquet format.
Usage:
LocaFile:
```
SELECT citycode FROM table1 INTO OUTFILE "file:///root/doris/" FORMAT AS PARQUET PROPERTIES
("schema"="required,int32,siteid;", "parquet.compression"="snappy");
```
BrokerFile:
```
SELECT siteid FROM table1 INTO OUTFILE "hdfs://host/test_sql_prc_2019_02_19/" FORMAT AS PARQUET
PROPERTIES (
"broker.name" = "hdfs_broker",
"broker.hadoop.security.authentication" = "kerberos",
"broker.kerberos_principal" = "test",
"broker.kerberos_keytab_content" = "base64" ,
"schema"="required,int32,siteid;"
);
```
Field `schema` is required, which defines the schema of a parquet file.
Prefix `parquet.` is the parquet file properties, like compression, version, enable_dictionary.
This CL mainly changes:
1. Support `SELECT INTO OUTFILE` command.
2. Support export query result to a file via Broker.
3. Support CSV export format with specified column separator and line delimiter.
