Support for C# Inline Action

[sschutten]

This adds support for the recently announced C# Inline Action. VS Code editor support is not there yet, however it's already possible to add csx files to the workflow by creating the files manually, where the name matches the action name.

The addition scans the logic app directory for any *.csx files and copies them to the working directory at the same relative paths. The reason for scanning the whole logic app directory is because it's possible to reuse code by importing *.csx files from locations outside of the workflow directory. Instead of trying to figure out which script imports which file this is the most straightforward solution.

The PR includes a test to verify the functionality.