[feature-wip](statistics) step6: statistics is available

[weizhengte]

Proposed changes

This pull request includes some implementations of the statistics(https://github.com/apache/incubator-doris/issues/6370).

users will be able to execute these sql such as "ANALYZE, SHOW ANALYZE, SHOW TABLE/COLUMN STATS..." to collect statistics information and query them.

Problem Summary:

Describe the overview of changes.

Checklist(Required)

1. Does it affect the original behavior: (Yes/No/I Don't know)
2. Has unit tests been added: (Yes/No/No Need)
3. Has document been added or modified: (Yes/No/No Need)
4. Does it need to update dependencies: (Yes/No)
5. Are there any changes that cannot be rolled back: (Yes/No)

Further comments

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