Add support for request body path parameters in v2

[darrelmiller]

see #885

• Added support for reading parameters "in: body"
• Added support for reading parameters "in: formdata"

[darrelmiller]

I decided not to implement writing re-used request bodies as path parameters in V2 for the following reasons:

• The behaviour would be inconsistent between re-used request bodies and reused parameters
• OpenAPI v3 doesn't support setting the requestBody at the path level and therefore it is a best practice to not use this in V2.
• An OpenAPI that was read that had identical request bodies across operations would not promote to path parameters, which would lead to inconsistent behaviour depending on how the DOM is constructed.

This means that the way it is currently implemented, we can successfully read request bodies as Path Parameters from V2 documents but they will be converted into operation parameters during the read.

[baywet]

• changelog entry in the CSproj

[darrelmiller]

• changelog entry in the CSproj

I would rather use the release notes in the CSProj to point to the release notes on GitHub than worry about updating this file with a description of every change.

[baywet]

• changelog entry in the CSproj

I would rather use the release notes in the CSProj to point to the release notes on GitHub than worry about updating this file with a description of every change.

Then may I suggest to log a new issue and have somebody on the team take care of that?

[darrelmiller]

• changelog entry in the CSproj

I would rather use the release notes in the CSProj to point to the release notes on GitHub than worry about updating this file with a description of every change.

Then may I suggest to log a new issue and have somebody on the team take care of that?

Done #923