add the ability to send images as attachment

[warengonzaga]

It is nice to have the ability to send images from Unthread to Discord and vice versa.

[warengonzaga]

@jakemccloskey or @bachonk, do you have any code snippets for uploading an attachment using Node.js? I get a 500 HTTP error message every time I try to upload using the form-data package.

[warengonzaga]

I made a clever idea of how to add images to Discord to Unthread Dashboard.