Ability To Specify S3 Bucket For All Deployment Bundle Types

I'm experiencing this with the `Create Application Version` and `Deploy` ElasticBeanstalk tasks, but after perusing the [source for this plugin](https://github.com/aws/aws-toolkit-azure-devops/blob/bae6b76e3bfd10a4188a93db6e026111710bdade/src/lib/beanstalkUtils.ts#L14), this probably applies to any task that automatically resolves an S3 bucket.

When using the aforementioned tasks, when **not** using a _Pre-existing deployment bundle_, there is no way to control what S3 bucket is using for the uploads that occur. The tasks issue what amount to a [create storage location](https://docs.aws.amazon.com/cli/latest/reference/elasticbeanstalk/create-storage-location.html) call and use whatever is returned. The existing S3 bucket and key parameters are _only_ used when the deployment bundle type is "pre-existing".

I would like the ability to specify what S3 bucket and key is used, regardless of deployment bundle type.

The alternatives force me into basically creating these pre-existing tasks myself, which defeats the entire point of the tasks and the plugin.

Start with src/lib/beanstalkUtils.ts, especially the bucket-resolution logic linked in the issue, then trace the Create Application Version and Deploy ElasticBeanstalk tasks and other tasks that resolve buckets automatically. Done means users can specify the S3 bucket and key for every deployment bundle type, rather than only for pre-existing bundles.

Written by the indexing model from the issue text.