New element related previews #116

Add the ability to show a list of element previews in the New Element dialog. The New Element dialog is shown after clicking on a button in an element dialog to add a related entry (ex. clicking "Answer Question" for a question element type). The preview elements should look the same as the list of elements shown on the main page, and be placed below the Submit button. There should be a divider line when any element previews are displayed, but if no element previews are displayed it should be hidden. The list should load progressively, like the main page, as it scrolls, which should also scroll the new element entry fields.

This list does not need to load real related entries, and can pull directly from the suggestion loader like the main page does for testing. The suggestion loader code should be commented out before submitting a PR, and no suggestions should be visible when running the code from the PR without uncommenting the suggestion loader code.