Revert "Add ability to delete threads"

This reverts commit 15821fe796.

app/templates/threads/delete_thread.html

@@ -1,22 +0,0 @@
-{% extends "base.html" %}
-
-{% block title %}
-	Delete thread in {{ thread.title }}
-{% endblock %}
-
-{% block content %}
-	<form method="POST" action="" class="card box_grey">
-		<input type="hidden" name="csrf_token" value="{{ csrf_token() }}" />
-
-		<h3 class="card-header">Delete {{ thread.title }} by {{ thread.author.display_name }}</h3>
-		<div class="card-body">
-			{{ thread.replies[0].comment | markdown }}
-		</div>
-		<div class="card-body">
-			<p>Deleting is permanent</p>
-
-			<a class="btn btn-secondary mr-3" href="{{ thread.getViewURL() }}">Cancel</a>
-			<input type="submit" value="Delete" class="btn btn-danger" />
-		</div>
-	</form>
-{% endblock %}