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

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

sitemap.php

@@ -0,0 +1,44 @@
+<?php
+
+// Constants.
+CONST BASE_URL = "https://nibblepoker.";
+const SITEMAP_LANGUAGES = ["", "en/", "fr/"];
+const SITEMAP_PAGES = [
+	"",
+	"about/",
+	"content/",
+	"content/lscom-cli",
+	"content/lscom-cli-dotnet",
+	"content/youtube-auto-archiver",
+	"content/excel-worksheet-password-remover",
+	"content/mc-expanded-iron-bundles",
+	"content/dotnet-arguments",
+	"links/",
+	"contact/",
+	"privacy/",
+];
+
+// Retrieving the requested TLD.
+switch($_SERVER['SERVER_NAME']) {
+	case "nibblepoker.lu":
+		$domain_tld = "lu";
+		break;
+	case "nibblepoker.com":
+		$domain_tld = "com";
+		break;
+	default:
+		http_response_code(400);
+		exit(1);
+}
+
+// Generating the sitemap.
+foreach(SITEMAP_LANGUAGES as $language_key) {
+	foreach(SITEMAP_PAGES as $page_path) {
+		echo(BASE_URL . $domain_tld. "/" . $language_key . $page_path . "\r\n");
+	}
+}
+
+// Finishing the response.
+http_response_code(200);
+exit(0);
+?>