ENH: Update How Attachments Are Done

## Is your feature request related to a problem?
When adding an attachment to the forum, one must use legacy methods to do so. This means manually choosing to upload something, looking for it, and then clicking to accept the selection, and then finally attaching it. This process is old, tedious, and doesn't help lead to user adoption of the feature or the forum itself. Most websites make it super-easy to do something like this.

## Describe the solution you'd like
We should implement a drag-and-drop landing zone feature to allow authorized end-users to upload an attachment.

## Describe alternatives you've considered
None yet.

## Additional context
None yet.