filter to show only specific resources in the AWS Toolkit windows

## Problem
Clobbered Explorer view with all account resources

## Expected behavior
I have a particular CDK application I am working on that consists of API Gateway, AWS Lambda function, and S3 bucket. I would like to apply a view filter in Explorer window (regex perhaps) to only show resources who's name matches the regex expression (e.g "myfeature-*") , that is only showing resources that I am actively working on and hide all other stacks/resources completely from the view. Often developers have a shared AWS account and drilling down each drop down of possible AWS resources is time consuming and clobbers the view.

Start with the AWS Toolkit Explorer view described in the issue and trace how API Gateway, Lambda, and S3 resources are presented. Define completion as a name or regex filter that hides nonmatching resources, then verify the view with a CDK application containing the listed resources.

Written by the indexing model from the issue text.