(GH-499) Add Editor Services Setting

This commit adds a user setting to allow the editor services to be
disabled. This is useful for scenarios where the user does not want the
advanced features of the language server, or won't ever have an
available PDK or Puppet-Agent install availble to run the language
server.

Author: jpogran

package.json

@@ -308,6 +308,11 @@
       "type": "object",
       "title": "Puppet",
       "properties": {
+        "puppet.editorService.enable": {
+          "type": "boolean",
+          "default": true,
+          "description": "Enable/disable advanced Puppet Language Features"
+        },
         "puppet.editorService.debugFilePath": {
           "type": "string",
           "default": "",