feat: Add JSON as a CLI output format (#215)

[dtzeng]

Issue #, if available: #215

Description of Changes

• Fix the agc configure format command as that was never working as-is.
• Added a new json format class that extends the formatting interface
• Added unit tests/reshuffled some shared types

Description of how you validated changes

Added unit tests

Testing agc configure format manually

dtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ agc configure format text
2022-02-04T14:21:24-08:00 𝒊  Setting default format to: 'text'
dtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ agc workflow describe hello
2022-02-04T14:21:35-08:00 𝒊  Describing workflow 'hello'.
WORKFLOW	hello	workflows/hello/hello.wdl	wdl	1.0
dtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ agc configure format table
2022-02-04T14:21:38-08:00 𝒊  Setting default format to: 'table'
dtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ agc workflow describe hello
2022-02-04T14:21:39-08:00 𝒊  Describing workflow 'hello'.
Name	TypeLanguage	TypeVersion	Source
hello	wdl		1.0		workflows/hello/hello.wdldtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ 
dtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ agc configure format json
2022-02-04T14:21:48-08:00 𝒊  Setting default format to: 'json'
dtzeng@u787d729b615b5f:/workplace/dtzeng/amazon-genomics-cli/examples/demo-wdl-project$ agc workflow describe hello
2022-02-04T14:21:49-08:00 𝒊  Describing workflow 'hello'.
{
	"Name": "hello",
	"TypeLanguage": "wdl",
	"TypeVersion": "1.0",
	"Source": "workflows/hello/hello.wdl"
}

tested json output of other commands can be seen in this doc: https://quip-amazon.com/klA5AaAOPF62/agc-json-format

Checklist

• If this change would make any existing documentation invalid, I have included those updates within this PR
• I have added unit tests that prove my fix is effective or that my feature works
• I have linted my code before raising the PR
• Title of this Pull Request follows Conventional Commits standard: https://www.conventionalcommits.org/en/v1.0.0/

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[tneely]

Can you please pull the args[0] value into a meaningful variable, especially since we reuse it across the code?

[dtzeng]

We aren't actually using args[0] within the same function
First we validate the args within Validate(args) then we pull out args[0] and assign it to opts.format