B-aws-cdk-parallel

* Add `--max-parallel-deployments` CLI flag to allow control of number the of stack deployments
that run at the same time. For larger projects this can significantly reduce the amount of
memory used when deploying a highly parallel stack.

* Remove `aws-cdk.core` dependency as it is probably not needed (if the project is developed
with AWS CDK anyways it will have `core` module installed). By removing this dependency both
`V1` and `V2` versions of AWS CDK should work.

* Fix dependencies.
* Remove unnecessary dependencies.

* cdk v2 compatibility.
* Use the stack displayName when calling the cdk deploy command.

* Improve parallel stack deployments by introducing `--exclusively` flag.
* Make dependencies graph beautiful.
* Output beautiful stack names (not aws cdk generated names).
* Fix --path CLI bug.

* Support "--parameters".
* Support "--context".
* Support specifying stacks.
* Add a lot more tests.