Plugin LWRP

`sensu_plugin` provides plugins from either a remote source over HTTP, or from a cookbook and installs them to Sensu's plugin directory.

##### Example usage:

Remote HTTP source
```ruby
sensu_plugin "https://raw.githubusercontent.com/sensu/sensu-community-plugins/master/plugins/http/check-http.rb"
```

Remote HTTP source with attributes
```ruby
sensu_plugin "https://raw.githubusercontent.com/sensu/sensu-community-plugins/master/plugins/http/check-http.rb" do
  filename 'my-http-check.rb'
  mode '0755'
  owner 'root'
  group 'sensu'
end
```

Cookbook source
```ruby
sensu_plugin "cookbook::filename"
```

Cookbook source with attributes
```ruby
sensu_plugin "cookbook::filename" do
  filename 'check-status.rb'
  mode '0755'
  owner 'root'
  group 'sensu'
end
```

Also supports "rights" attribute for Windows installs