feat: 個人宛てお知らせ機能 (#107)

* feat: 個人宛てお知らせ機能

* Remove unused import

* Update packages/backend/src/server/api/endpoints/admin/announcements/create.ts

Co-authored-by: riku6460 <17585784+riku6460@users.noreply.github.com>

* Update packages/frontend/src/pages/announcements.vue

Co-authored-by: riku6460 <17585784+riku6460@users.noreply.github.com>

* Restore breakline

* 一般向けAPIにはuserオブジェクトを提供しない

* fix

* Fix

* Update packages/misskey-js/src/entities.ts

Co-authored-by: riku6460 <17585784+riku6460@users.noreply.github.com>

* Fix

* Update misskey-js.api.md

* Fix lint

* 他のテーブルに合わせて character varying(32) にした

* count クエリを1つにまとめた

* user を pack するようにした

* いろいろ修正

* 個人宛てのお知らせの表示を改善

* Update misskey-js.api.md

* Merge migration scripts

* Fix

* Update packages/backend/migration/1688647797135-userannouncement.js

Co-authored-by: riku6460 <17585784+riku6460@users.noreply.github.com>

* Update packages/backend/src/models/entities/Announcement.ts

Co-authored-by: まっちゃとーにゅ <17376330+u1-liquid@users.noreply.github.com>

* Fix

* Update migration script

---------

Co-authored-by: CyberRex <hspwinx86@gmail.com>
Co-authored-by: まっちゃとーにゅ <17376330+u1-liquid@users.noreply.github.com>

packages/misskey-js/etc/misskey-js.api.md

@@ -26,6 +26,8 @@ type Announcement = {
     title: string;
     imageUrl: string | null;
     isRead?: boolean;
+    isPrivate: boolean;
+    closeDuration: number;
 };
 
 // @public (undocumented)
@@ -544,6 +546,7 @@ export type Endpoints = {
             withUnreads?: boolean;
             sinceId?: Announcement['id'];
             untilId?: Announcement['id'];
+            privateOnly?: boolean;
         };
         res: Announcement[];
     };