Fix inviting others to private messages.

It looks like `PrivateMessageMapComponent` was recently converted into a view which don't have `sendAction` defined. 

Also note that the following files in `app/assets/javascripts/discourse/components` are (except for the last one) actually views and not components. The documentation string and template location is also incorrect. I haven't moved them to the correct places since I figured it was possible you might be in the middle of refactoring them.

* private_message_map_component.js
* toggle_summary_content.js
* topic_map_component.js
* keyboard_shortcuts_component.js