Add support for ASC and DESC in CREATE TABLE column constraints for SQLite.

[caldwell]

See: https://sqlite.org/lang_createtable.html

I didn't directly copy the AUTOINCREMENT code right above the diff because I happened to read #1430 the other day. Instead I created a new function in Dialect and enabled it in SQLiteDialect and GenericDialect—I hope this is ok.

I'm also a little disappointed that I couldn't deduplicate the ASC and DESC handling in src/parser/mod.rs. Maybe if/when if let chains are stabilized they could be consolidated cleanly…

[coveralls]

Pull Request Test Coverage Report for Build 11223307115

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 21 of 25 (84.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.003%) to 89.305%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/dialect/generic.rs	1	2	50.0%
src/dialect/sqlite.rs	1	2	50.0%
src/dialect/mod.rs	0	2	0.0%

Totals
Change from base Build 11186281805:	-0.003%
Covered Lines:	30010
Relevant Lines:	33604

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💛 - Coveralls

[alamb]

Looks good (again) to me @caldwell

Thank you for breaking these PRs up into smaller ones for review

cc @iffyio

[iffyio]

LGTM!