(QENG-1212) Improve module installation experience

Prior to this puppet module installation was carried out with either
`puppet_module_install` or `copy_module_to`. This replaces them with a
method `install_dev_puppet_module` that will install either via scp or
pmt from a staging forge depending on arguements and environment.
It is possible for `module_name` to be `nil`. For instance, when `opts[:source]` equals `./` (the default being set in this method). This will cause the `scp` call below to fail during `File.join`.