Added AWS SSM Parameter Store for CloudGuard Credential and CodePipeline

[jaydenaung]

Updates:

• CloudGuard API key and secret will be securely stored as parameters in AWS SSM parameter store instead of exporting them to build environment in plain text (in buildspec.yml). This addresses security risks around plain text credentials embedded in buildspecs.yml.
• Creation of In-line policy using JSON which is required by Codebuild to access SSM parameters (CloudGuard credentials)
• In buildspec.yml, instead of exporting CloudGuard API and secret, two command lines will be embedded in order to call AWS API to securely access CloudGuard credentials stored in AWS SSM parameter store.
• Added AWS Codepipeline Integration (Current tutorial only discusses about integrating Shiftleft with Codebuild.) This shows SHIFTLEFT works with CICD pipeline on AWS.
• Added my-codepipeline.json for easy creation of a pipeline using AWS CLI
• Added screenshots