Add identifier quote style to Dialect trait

[backkem]

This relates to apache/datafusion#9517 where we're adding an SQL unparser to turn DataFusion Expr/Plans back into SQL.

I extended the method to allow passing the identifier value. This may be helpful in case we want to add heuristics to only add quotes if truly needed by the dialect.

[backkem]

cc @alamb

[alamb]

Looks good to me -- thank you @backkem

I think before we could merge this PR we need some tests ( mostly so if it got broken by accident in the future we would know because a test would fail)

[coveralls]

Pull Request Test Coverage Report for Build 8238316231

Details

• 12 of 15 (80.0%) changed or added relevant lines in 4 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.005%) to 87.859%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/dialect/mysql.rs	0	1	0.0%
src/dialect/mod.rs	10	12	83.33%

Files with Coverage Reduction	New Missed Lines	%
src/dialect/mod.rs	1	80.8%

Totals
Change from base Build 8208430635:	-0.005%
Covered Lines:	20501
Relevant Lines:	23334

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💛 - Coveralls

[backkem]

I added a basic test. It feels somewhat artificial but I didn't want to build additional 'unparser' logic in the test case.

[alamb]

I added a basic test. It feels somewhat artificial but I didn't want to build additional 'unparser' logic in the test case.

I agree it feels somewhat forced, but I think that is also OK in this case. We can improve things later if necessary.

Thank you @backkem