Add DM requests

Currently, leaving DMs open invites anyone to spam my open DMs and to drown out DMs I want to have open.

Adding DM requests would entail adding a folder of "unaccepted DM requests" in the same list as the "personal notes" button, in which there is a list of users (and a preview of the message they sent). On the right of each entry, there would be a "deny" and "accept" button. Clicking on the body is the same as clicking "accept". Functionality wise, denying a DM request just removes the entry. Accepting (or clicking the body) opens the DM in your regular DM list. DM requests should be a toggle in user and channel settings. DM requests do not produce sound, nor are the user profile pictures shown in the sidebar list. Instead, only a badge counter is shown on the DMs icon.

I believe Discord describes this better: https://support.discord.com/hc/en-us/articles/7924992471191-Message-Requests