replace DMs with ephemeral messages

[DecentralizedDan]

A user pointed out that they could not receive a DM for the webserver URL bc their DMs are off.

• The ideal solution is to switch to using ephemeral messages
• These are faster (no switching to a DM), equally secure, and easy to implement

[DecentralizedDan]

https://support.discord.com/hc/en-us/articles/1500000580222-Ephemeral-Messages-FAQ