Add table-level constraint parsing for CREATE TABLE

[kyleconroy]

Add support for parsing named table constraints (CONSTRAINT name ...)
including PRIMARY KEY, UNIQUE, FOREIGN KEY, and CHECK constraints.

Changes:

• Add parseNamedTableConstraint() for CONSTRAINT name ... syntax
• Add parseUnnamedTableConstraint() for constraints without names
• Add parsePrimaryKeyConstraint() with column sort order support
• Add parseUniqueConstraint() with CLUSTERED/NONCLUSTERED
• Add parseForeignKeyConstraint() with REFERENCES clause
• Add parseCheckConstraint() for CHECK expressions
• Add parseColumnWithSortOrder() for ASC/DESC column specifications
• Fix foreignKeyConstraintToJSON() to output ReferencedTableColumns
• Always output DeleteAction/UpdateAction with default "NotSpecified"

Enables tests:

• BaselinesCommon_TSqlParserTestScript3
• TSqlParserTestScript3