Add code coverage to conjur-api-dotnet

Add code coverage to this project.

Acceptance Criteria:

Code coverage should be measured across all tests defined in this repository every time a build is run in any branch.
Coverage report should include:
- Line Coverage (including highlighting which lines are covered and which are not - not just giving a percentage)
- Conditional Coverage
- Optionally, other kinds of coverage such as Package, Class, File, or Method coverage
Coverage report should be created in or converted to Cobertura format as part of build to allow for ingestion into coverage aggregation tools
Coverage report should be archived in the Jenkins build using the cobertura command as shown at https://github.com/cyberark/conjur-api-ruby/blob/072d21e01e46382ee4d577e180c1269f8ff9f36e/Jenkinsfile#L27
Coverage report should be uploaded to Code Climate with each build

cyberark / conjur-api-dotnet