DNN-6208 Make HTML Editor Manager separate from editor provider

The HTML Editor Manager module was part of the RadEditorProvider, we've pulled it out into its own module.
This module loads the configuration control based on an attribute in the provider entry in the web.config
DNN-6208 Modify the RadEditor manifest to include new settingControlPath attribute.
DNN-6208 Removed controls and code from RadEditor that was used to read/write to the web.config and some code cleanup.
DNN-6208 Fixed issue with passing wrong Id to Upgrade.RemoveModule