Add the Transit tables to the CDK

[justindra]

Add all the DynamoDB Tables to the CDK for each of the tables in the Transit module.

• Add the agencies table
  • PartitionKey - id
• Add the routes table
• Add the services table
  • PartitionKey - id
  • GSI1 - agency_id:end_date
• Add the Stops table
• Add the Trips table
  • PartitionKey - route_id
  • SortKey - service_id
  • GSI1 - agency_id:service_id
• Add the DailyData Table
  • PartitionKey - agency_id
  • SortKey - date