[fix-234][core] Fix to flink jar cannot be monitored

[Feature-228][pom] Modify version to 0.6.1-SNAPSHOT

[Feature-223][style] add checkstyle

[Fix-224] [metadata-hive]  Fix HiveJDBC  Multiple SQL Query

 Fix issues related to hive JDBC

## Brief change log

- 1. Fix bug of querying multiple SQL in hive JDBC mode
- 2. Fix the result set data type conversion of hive JDBC query results

## Verify this pull request
- Added dlink-metadata-hive tests for   MultipleSQLTest

fix(metadata):  MySqlDriver Flink Column Type Conversion error

[fix-214][gateway,common] Failed to submit fink jar when configuratio…

[Feature-215][docs] add developer documentation

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