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/frontend/src/pages/admin/settings.vue

@@ -159,6 +159,11 @@ SPDX-License-Identifier: AGPL-3.0-only
 							<template #label>{{ i18n.ts.enableBotTrending }}<span v-if="otherForm.modifiedStates.enableBotTrending" class="_modified">{{ i18n.ts.modified }}</span></template>
 							<template #caption>{{ i18n.ts.turnOffBotTrending }}</template>
 						</MkSwitch>
+
+						<MkTextarea v-model="otherForm.state.robotsTxt">
+							<template #label>{{ i18n.ts.robotsTxt }}<span v-if="otherForm.modifiedStates.robotsTxt" class="_modified">{{ i18n.ts.modified }}</span></template>
+							<template #caption>{{ i18n.ts.robotsTxtDescription }}</template>
+						</MkTextarea>
 					</div>
 				</MkFolder>
 
@@ -369,10 +374,12 @@ const serviceWorkerForm = useForm({
 const otherForm = useForm({
 	enableAchievements: meta.enableAchievements,
 	enableBotTrending: meta.enableBotTrending,
+	robotsTxt: meta.robotsTxt,
 }, async (state) => {
 	await os.apiWithDialog('admin/update-meta', {
 		enableAchievements: state.enableAchievements,
 		enableBotTrending: state.enableBotTrending,
+		robotsTxt: state.robotsTxt,
 	});
 	fetchInstance(true);
 });