feat(serialization): Use friendly names for artifact types

[luispollo]

Addresses #557 by introducing "friendly names" for artifact types (i.e. lower-case names as opposed to the default enum value names). Given that all current friendly names match the upper-case enum names, this could probably be even simpler, but when I started we had a conversion between "docker" and DOCKER_TYPE and so I figured it's OK to have a place to add that kind of logic if we ever have other types that don't match the friendly name. The @JsonCreator factory method also allows for backwards-compatibility with existing specs still using the upper-as names.

[luispollo]

This will conflict with @emjburns' change in #556. I'll wait for her to merge and then resolve the conflict.

[luispollo]

@emjburns @erikmunson Please review.

[erikmunson]

this is great! thanks Luis. FWIW, it appears Emily switched the enum value to DOCKER after Rob and I bugged her about it, so you may be able to omit some of the mapping stuff here (maybe? I don't know these things): https://github.com/spinnaker/keel/pull/556/files#diff-2cd4b503a4f236b6c490d3fcccb3481dR9

[luispollo]

Hey @erikmunson, yes, I noticed that after I made my change. I'll remove the line to convert from "docker" to DOCKER_IMAGE as soon as @emjburns merges her PR.

[luispollo]

@emjburns @erikmunson This is now rebased after Emily's PR was merged. @robfletcher If you want to take a look as well, please do!

[emjburns]

😆 looks good! This will work if you have either deb or DEB in the yaml, right?

[erikmunson]

Oh related question to Emily's — what will the export resource endpoint emit in its YAML for delivery artifacts after this change? Ideally it would prefer the lower case form.

[luispollo]

😆 looks good! This will work if you have either deb or DEB in the yaml, right?

@emjburns Right, it will work with both formats. I added a test for that as well.

Oh related question to Emily's — what will the export resource endpoint emit in its YAML for delivery artifacts after this change? Ideally it would prefer the lower case form.

@erikmunson Yes, JSON output will be using the friendly format. For example:

---
metadata:
  serviceAccount: "keel@spinnaker.io"
apiVersion: "ec2.spinnaker.netflix.com/v1"
kind: "cluster"
spec:
  moniker:
    app: "keeldemo"
    stack: "main"
  imageProvider:
    deliveryArtifact:
      name: "keeldemo"
      type: "deb"
  locations:
    account: "test"
    subnet: "internal (vpc0)"
    vpc: "vpc0"
    regions:
    - name: "us-west-2"
  launchConfiguration:
    instanceType: "m5.large"
    ebsOptimized: true
    iamRole: "keeldemoInstanceProfile"
    keyPair: "nf-test-keypair-a"
    instanceMonitoring: false
  capacity:
    min: 1
    max: 1
    desired: 1
  dependencies:
    loadBalancerNames:
    - "keeldemo-main-clb"
    securityGroupNames:
    - "keeldemo"
    - "nf-datacenter"
    - "nf-infrastructure"

[luispollo]

@emjburns If you're OK with it, could you please add the ready to merge label?