chore: update CDK postgres E2Es to use Data API

[fuelvin1]

Description of changes

• Adds new methods for alternate flow using the Aurora serverless V2 Postgres clusters as part of setup and teardown.
• Uses Data API to provision test database and tables.

CDK / CloudFormation Parameters Changed

Issue #, if available

Description of how you validated changes

Update sql-models-2 test to use postgres and verified it passes.

Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)
• New AWS SDK calls or CloudFormation actions have been added to relevant test and service IAM policies
• Any CDK or CloudFormation parameter changes are called out explicitly

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[palpatim]

Rework this to include dbname as a parameter, to avoid potential SQL injection if dbname is ever compromised. (Plus, it's a good habit to get into to not interpolate into SQL if you can avoid it). In this case, the risk is minimal since we generate the dbname, but if in future we decided "hey, let's let dbname be specified by an environment variable", then we'd be open to executing SQL with untrusted input.

[palpatim]

nit: command is pretty generic, especially since you're issuing multiple commands in the body of this function

Suggested change

	const command = new CreateDBClusterCommand(params);
	const createClusterCommand = new CreateDBClusterCommand(params);

[palpatim]

As above, rdsResponse is pretty generic. Consider something that more explicitly defines the purpose of the variable

Suggested change

	const rdsResponse = await rdsClient.send(command);
	const createClusterResponse = await rdsClient.send(createClusterCommand);

[palpatim]

nit: as elsewhere, the name is pretty generic

Suggested change

	const command = new ExecuteStatementCommand(createDBInput);
	const createDbCommand = new ExecuteStatementCommand(createDBInput);

[palpatim]

very nit: you don't actually know that the incoming queries are for creating tables -- some may be altering tables, creating indexes, or even updating tables with new records. :) In this case, a more generic name is appropriate.

Suggested change

	const createTableInput: ExecuteStatementCommandInput = {
	const executeStatementInput: ExecuteStatementCommandInput = {

[palpatim]

Suggested change

	const createTableResponse = await client.send(new ExecuteStatementCommand(createTableInput));
	console.log('Create table response: ' + JSON.stringify(createTableResponse));
	const executeStatementResponse = await client.send(new ExecuteStatementCommand(createTableInput));
	console.log('executeStatementResponse: ' + JSON.stringify(executeStatementResponse));

[sundersc]

As this is only a test resource, can we lower these values?