Please integrate discord more with macOS

The Discord mac app feels very cumbersome to use. It doesn't make use of any of the features macOS has to offer. 

1. Better App menu. Right now, everything in Discord has to be done through context menus. But it would be a lot nicer if you could do everything through the app menus at the top of the screen. Not only would it make finding out what you can do a lot easier, Because macOS lets you assign keyboard shortcuts in System Preferences, it would also allow users to assign their own shortcuts.

2. Ability to reply to notifications. Right now, the iOS version of Discord lets you reply to messages from the notification. Currently, macOS does not provide this same functionality.

3. Newer app icon that matches the latest version of macOS. Currently, the Discord icon is round. It should be in a similar shape to all the other apps in macOS Big Sur.

4. Better default shortcuts. Right now, a lot of the macOS Discord shortcuts feel really awkward to use. Some of them are even outliers and should be changed to match everything else. Here are some examples:

- The normal shortcut for opening help is ⌘? (Command - Shift - /). But in Discord, its ⌘⇧H (Command - Shift - H). 

- The shortcuts in Messages.app for moving between conversations is ⌃⇥ (Control - Tab) and ⌃⇧⇥ (Control - Shift - Tab). But in Discord, the shortcuts for moving between channels is ⌥↑ and ⌥↓ (Option - Up) and (Option - Down)

- Starting a new message should be ⌘N (Command - N). But in Discord, the shortcut for starting a new Direct Message is ⌘K (Command - K)

- The shortcut in Mail.app for marking an email as read is ⌘⇧L (Command - Shift - L). But in Discord, the shortcut for marking a server as read is ⇧⎋ (Shift - Escape)