Add wrapper for http response with version

[etrexel]

Description

Adds a new type that represents the response for an http request. This type insulates the internal implementation from external consumers and adds a version field so that we can track changes that could break external consumers. For now the format of the response is still not that formally typed, but this gives a starting point.

Fixes #261

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

• Ran a Ratify request and validated that new version field was part of the response

Checklist:

• Does the affected code have corresponding tests?
• Are the changes documented, not just with inline documentation, but also with conceptual documentation such as an overview of a new feature, or task-based documentation like a tutorial? Consider if this change should be announced on your project blog.
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have appropriate license header?

[susanshi]

Hi @etrexel , i see this change requires a doc update, could you point us to the doc?