Custom emoji & Sticker support (#686)

* Remove comments

* Show custom emoji first in suggestions

* Show global image packs in emoji picker

* Display emoji and sticker in room settings

* Fix some pack not visible in emojiboard

* WIP

* Add/delete/rename images to exisitng packs

* Change pack avatar, name & attribution

* Add checkbox to make pack global

* Bug fix

* Create or delete pack

* Add personal emoji in settings

* Show global pack selector in settings

* Show space emoji in emojiboard

* Send custom emoji reaction as mxc

* Render stickers as stickers

* Fix sticker jump bug

* Fix reaction width

* Fix stretched custom emoji

* Fix sending space emoji in message

* Remove unnessesary comments

* Send user pills

* Fix pill generating regex

* Add support for sending stickers

src/app/organisms/sticker-board/StickerBoard.scss

@@ -0,0 +1,60 @@
+@use '../../partials/dir';
+
+.sticker-board {
+  --sticker-board-height: 390px;
+  --sticker-board-width: 286px;
+  display: flex;
+  height: var(--sticker-board-height);
+
+  &__container {
+    flex-grow: 1;
+    min-width: 0;
+    width: var(--sticker-board-width);
+    display: flex;
+  }
+
+  &__content {
+    min-height: 100%;
+  }
+
+  &__pack {
+    margin-bottom: var(--sp-normal);
+    position: relative;
+
+    &-header {
+      position: sticky;
+      top: 0;
+      z-index: 99;
+      background-color: var(--bg-surface);
+  
+      @include dir.side(margin, var(--sp-extra-tight), 0);
+      padding: var(--sp-extra-tight) var(--sp-ultra-tight);
+      text-transform: uppercase;
+      box-shadow: 0 -4px 0 0 var(--bg-surface);
+      border-bottom: 1px solid var(--bg-surface-border);
+    }
+    &-items {
+      margin: var(--sp-tight);
+      @include dir.side(margin, var(--sp-normal), var(--sp-extra-tight));
+      display: flex;
+      flex-wrap: wrap;
+      gap: var(--sp-normal) var(--sp-tight);
+
+      img {
+        width: 76px;  
+        height: 76px;
+        object-fit: contain;
+        cursor: pointer;
+      }
+    }
+  }
+
+  &__empty {
+    width: 100%;
+    height: var(--sticker-board-height);
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    text-align: center;
+  }
+}