Redesign ShardingMetaData module.

[tristaZero]

Feature Request

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Though we have ShardingMetaData now, but it can not meet all the needs for some important scenarios, we need to redesign ShardingMetaData module. The tasks are as follows:

• Implement the interface getMetaData of JDBC.
• Read column type when needed.
• Consider about the interface of ShardingResultSetMeta to shade the real column label.

#1321 can be solved in this issue, Please focus on this issue.

[KomachiSion]

refer to #1774 .