Channel List Header Data from DB (#5807)

* Renames header

* Adds Server Display Name Context

* Adds server and team name to header

* Snapshot fail fixed

* rename serverUrl context to server and include displayName

* Add server display name and use only team display name in channel list header

* Improve channel_list test

* Fix channel list on tablets when team sidebar is present

* Fix Server icon color

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

app/context/server/index.tsx

@@ -0,0 +1,54 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import React, {ComponentType, createContext} from 'react';
+
+type Props = {
+    server: ServerContext;
+    children: React.ReactNode;
+}
+
+type WithServerUrlProps = {
+    serverUrl: string;
+}
+
+type ServerContext = {
+    displayName: string;
+    url: string;
+}
+
+const ServerContext = createContext<ServerContext>({displayName: '', url: ''});
+const {Provider, Consumer} = ServerContext;
+
+function ServerUrlProvider({server, children}: Props) {
+    return (
+        <Provider value={server}>{children}</Provider>
+    );
+}
+
+export function withServerUrl<T extends WithServerUrlProps>(Component: ComponentType<T>): ComponentType<T> {
+    return function ServerUrlComponent(props) {
+        return (
+            <Consumer>
+                {(server: ServerContext) => (
+                    <Component
+                        {...props}
+                        serverUrl={server.url}
+                    />
+                )}
+            </Consumer>
+        );
+    };
+}
+
+export function useServerDisplayName(): string {
+    const server = React.useContext(ServerContext);
+    return server.displayName;
+}
+
+export function useServerUrl(): string {
+    const server = React.useContext(ServerContext);
+    return server.url;
+}
+
+export default ServerUrlProvider;