qbusiness: add L2 Constructs for Amazon Q Business

[jumic]

Is your feature request related to a problem? Please describe.
Amazon Q Business was released at last year's re:Invent. CloudFormation resources are available to deploy Q Business. However, L2 constructs are missing in AWS CDK.

Would you be willing to help with a PR?

• Yes, absolutely
• Yes, with some guidance
• Unfortunately no time :'-(

Describe the solution you'd like

Add L2 constructs to deploy Q Business. Solution design is open.

Describe alternatives you've considered

Use L1 constructs.

Additional context

Please let me know if you will accept this contribution. Then I will start working on it.