MM-40203: permalink modal viewer for mentions (#5999)

* Permalink initial commit

* Fixes: 10 items per page

* MM-40203: permalink modal viewer for mentions

Is triggered by pressing on an item in mentions,
and shows posts around that item, including the item in a modal.

* Adds previously deleted file

* address feedback

* Move showPermalink as a remote action

* address more feedback

* fetchPostsAround to only return PostModel

* Attempt to autoscroll to highlighted item

* Permalink to not highlight saved and pinned posts

* Add bottom margin using insets to permalink screen

* Use lottie loading indicator

* Switch to channel

* Missing translation string

Co-authored-by: Elias Nahum <nahumhbl@gmail.com>

app/utils/permalink/index.ts

@@ -0,0 +1,36 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {Keyboard} from 'react-native';
+
+import {dismissAllModals, showModalOverCurrentContext} from '@screens/navigation';
+import {changeOpacity} from '@utils/theme';
+
+let showingPermalink = false;
+
+export const displayPermalink = async (teamName: string, postId: string, openAsPermalink = true) => {
+    Keyboard.dismiss();
+    if (showingPermalink) {
+        await dismissAllModals();
+    }
+
+    const screen = 'Permalink';
+    const passProps = {
+        isPermalink: openAsPermalink,
+        teamName,
+        postId,
+    };
+
+    const options = {
+        layout: {
+            componentBackgroundColor: changeOpacity('#000', 0.2),
+        },
+    };
+
+    showingPermalink = true;
+    showModalOverCurrentContext(screen, passProps, options);
+};
+
+export const closePermalink = () => {
+    showingPermalink = false;
+};