Add additional build info properties and parameterize VcsType

[joeypiccola]

This PR does two things.

1. Allows users to set the VcsType used in the build information. Defaults to GitHub.
2. Add the additional build information properties VcsRoot and VcsCommitNumber. Build information submitted without a VcsRoot is 100% functional but complains about No VCS root configured (shown below).
   

This may also fix an issue when create-release is called. My create-release job errors with the following.

Creating release...
There was a problem with your request.

 - GitHub: No VCS root configured

Error from Octopus Server (HTTP 400 BadRequest)
Exit code: -7

[jschwanz]

You can probably make this dynamic, too, by using << pipeline.project.type >>. See https://circleci.com/docs/2.0/variables#pipeline-values.