AWS Codepipeline for VAMS

[amigitamz]

Issue #, if available:
N/A

Description of changes:
Add CI/CD functionality by integrating VAMS with AWS CodePipeline. The codepipeline stack deploys the required infrastructure for deploying the CodePipeline. This CodePipeline will connect to the user's remote repository(fork from VAMS) and synthesize and deploy VAMS stacks using AWS CodeBuild.

Following changes were made -

1. Added "codepipeline" folder at the root level with stack for deploying CodePipeline
2. Updated readme with instructions for deploying the CodePipeline and performing continuous deployments using the new pipeline.
3. Architecture for the new integration.
4. Add watchAll flag

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