Implement new attachment parameters

[Middledot]

Summary

A few parameters were added to attachments urls such as an expiry timestamp and a auth signature for retrieving it.

What is the feature request for?

The core library

The Problem

There parameters are not implemented

The Ideal Solution

These parameters should eventually be implemented

The Current Solution

There are not implemented, so there is no current solution

Additional Context

There is currently no set date for when authentication/expiring attachments will be enforced (except for a "later this year")

DDevs announcement

[Lulalaby]

Please note that the end spec isn't out yet.
Some internal info is floating around but nothing notable yet.

So far, only the full url with signature params needs to be called via GET to get the attachment.

[NeloBlivion]

Closed in #2342