Adding robots.txt override via admin control panel

This is a requested low priority feature in #418 - I created the changes
to follow similarly to how the Instance Description is handled.

packages/backend/src/server/web/ClientServerService.ts

@@ -488,7 +488,14 @@ export class ClientServerService {
 		});
 
 		fastify.get('/robots.txt', async (request, reply) => {
-			return await reply.sendFile('/robots.txt', staticAssets);
+			if (this.meta.robotsTxt) {
+				let content = '';
+				content += this.meta.robotsTxt;
+				reply.header('Content-Type', 'text/plain');
+				return await reply.send(content);
+			} else {
+				return await reply.sendFile('/robots.txt', staticAssets);
+			}
 		});
 
 		// OpenSearch XML