Cleaned up some code, Replaced robots.txt & sitemap.txt with PHP code, Updated gitignore rules

Update .gitignore, .htaccess, and 11 more files...

robots.php

@@ -0,0 +1,20 @@
+<?php
+// Returning a domain-specific "robots.txt" file based on the requested host.
+switch($_SERVER['SERVER_NAME']) {
+	case "nibblepoker.lu":
+		print("User-agent: *\r\n");
+		print("Allow: /\r\n\r\n");
+		print("Sitemap: https://nibblepoker.lu/sitemap.txt\r\n");
+		break;
+	case "nibblepoker.com":
+		print("User-agent: *\r\n");
+		print("Allow: /\r\n\r\n");
+		print("Sitemap: https://nibblepoker.com/sitemap.txt\r\n");
+		break;
+	default:
+		http_response_code(400);
+		exit(1);
+}
+http_response_code(200);
+exit(0);
+?>