#687 Added Delete button for post types on Register Types/Taxes list

[tw2113]

@alokstha1 Making this just for some discussion sake.

Is there any super specific reason why we're going with a separate js file for this, instead of sticking with the already existing js file? I know it may be just a case of separation of concern, but I also feel like we don't use javascript THAT much with the plugin, and one file would suffice.