Author CircleCI Orb to Simplify clair-cicd Usage

[simonsdave]

To use clair-cicd in a CircleCI pipeline the following step is typically authored

- run:
    name: Run docker image vulnerability risk assessment
    command: |
      curl \
        -s \
        -L \
        https://raw.githubusercontent.com/simonsdave/clair-cicd/master/bin/assess-image-risk.sh | \
        bash -s -- --verbose --whitelist 'file://clair-cicd-whitelist-dev-env.json' "${DOCKER_TEMP_IMAGE}"

That's not too bad but an Orb would simplify the above and provide a layer of abstraction so the invocation could be changed and consumers of clair-cicd would not be affected.

See this for how to author an Orb.