Fix JSON Lint Issues.

[Matthew-Grayson]

🗣 Description

Apply pretty-format-json to all *.json files.
Change censysCertificatesSample.json and censysIpv4Sample.json to *.txt file type.

💭 Motivation and context

Closes issue #48
The Censys sample data json files are not true json. They are line-separated json objects vs an array of json objects. As such, they get flagged by both pretty-format-json and check-json. Converting each file to a properly formatted json array requires refactoring the test suites that use them. For expedience, I converted them to *.txt files.

🧪 Testing

Existing tests pass.

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced
  in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated
  to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release.

[schmelz21]

Confirmed json linting fixed.

[DJensen94]

LGTM