Mergeback for 0.5.0

Previously the trade offs link was relative to the README, however, on the Forge this does not work.  This commit updates the link to be absolute.

(MODULES-7437) Use absolute link in README

Converted "on(agent...)" tests to use testmode switcher method "execute_manifest()" method
Removed now unnecessary "windows_agents.each" guards around the new "execute manifest" calls

Modules 6474

(MAINT) Update Readme

This commit converts the module for use by the Puppet Development Kit (PDK).
Note that the rubocop rules are disabled and the violations will be fixed in
later commits.

 - Prior to this commit, all types would report the `dsc` type as their
   identity. This is problematic for the sake of reporting as every type
   of resource is grouped together under `dsc`, rather than the specific
   `resource_name` modeled in a manifest.

   This new approach allows for types to report under something more
   useful that indicates the original DSC resource type specified in the
   resource_name attribute.

   For instance, given a manifest with the following resources:

   dsc { 'sample_file':
     resource_name     => 'File',
     module            => 'PSDesiredStateConfiguration',
     properties        => {
       ensure          => 'present',
       contents        => 'hello',
       destinationpath => 'c:\\test.txt',
     }
  }

  dsc { 'lmhosts':
     resource_name     => 'Service',
     module            => 'PSDesiredStateConfiguration',
     properties        => {
       name            => 'lmhosts',
       ensure          => 'present',
       state           => 'running',
     }
  }

  The report now shows:

  * Dsc_lite_file[sample_file]    Unchanged
  * Dsc_lite_service[lmhosts]     Unchanged

  Instead of what it previously reported:

  * Dsc[sample_file]              Unchanged
  * Dsc[lmhosts]                  Unchanged

 - Selection of the PowerShell code was previously determined by type,
   but given it has changed to being specified as :Dsc_lite_XXXX, its
   not as easy to do that anymore. Instead, add a simple boolean
   property to the generic dsc wrapper that may be checked instead.

 - Note that parameter validation for `module`, `resource_name` and
   properties does not currently work, but will be fixed in another
   ticket by adding a global validator. The `type` method performs some
   additional guarding around usage of the `resource_name` parameter
   for 2 reasons:

   * It's unclear if the parser or other logic in Puppet uses the type
     name without the resource being instantiated fully with values from
     a manifest
   * Due to the incorrect validation, the PE console errors with the
     following message when `resource_name` is left unspecified:

   undefined method `value` for nil:NilClass

…resources-with-specific-types

(MODULES-7178) Report types dynamically

(MODULES-7400) PDK Convert dsc_lite

This commit uses global type validation to require the `module`,
`resources_name`, and `properties`, instead of `isrequired`. `isrequired`
does not work ( see https://projects.puppetlabs.com/issues/4049 / https://tickets.puppetlabs.com/browse/PUP-1591 )

This also removes the tests for situations where `resource_name` is
not supplied, as the prior commit adds validation to ensure
`resource_name` is supplied. The tests would always fail because
`resource_name` is now required.

…equired-parameters

(MODULES-7485) Fix validation for required parameters

 - 914d934 introduced a new feature for
   dsc_lite. In situations where the proper WMF5 version was not
   available, a warning would be generated using the Puppet.warn_once
   helper.

   However, it was not realized that Puppet 4 and Puppet 5 have
   different numbers of arguments that can be passed to warn_once, and
   that only Puppet 5 supported changing warning to error.

   That change was introduced in
   puppetlabs/puppet@3d82337

 - Calling a Ruby method with too many arguments causes a Ruby crash and
   results in a completely terminated Puppet run that produces no report
   for the master. In other words, this is a completely catastrophic
   failure case.

 - Resolve this problem by checking the arity of the Puppet.warn_once
   call to send the right number of arguments on Puppet 4.

   The concession was made to vary the message type on Puppet 4 (warning)
   vs Puppet 5 (error), because the alternative solution did not
   preserve the warn_once style behavior. Instead, it would have
   produced an error for every single dsc_lite resource, which was far
   less desirable.

…-4-less-than-WMF5

(MODULES-7554) Fix crash on Puppet 4 / WMF < 5

This commit updates the changelog and metadata in
preparation for the release of the module at 0.6.0

…574-release-prep-060

(MODULES-7574) Release prep for 0.6.0