Add support of FREEZE|UNFREEZE PARTITION syntax for ClickHouse

[git-hulk]

ClickHouse supports using the FREEZE|UNFREEZE operation in ALTER TABLE to freeze or unfreeze partition.

References:

• https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#freeze-partition
• https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#unfreeze-partition

[coveralls]

Pull Request Test Coverage Report for Build 10388478580

Details

• 66 of 72 (91.67%) changed or added relevant lines in 3 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.01%) to 89.053%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/parser/mod.rs	20	22	90.91%
src/ast/ddl.rs	12	16	75.0%

Files with Coverage Reduction	New Missed Lines	%
src/parser/mod.rs	3	93.22%

Totals
Change from base Build 10388253404:	0.01%
Covered Lines:	28178
Relevant Lines:	31642

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💛 - Coveralls

[git-hulk]

cc @iffyio

[iffyio]

LGTM! cc @alamb

[alamb]

Thanks @git-hulk and @iffyio