Update Discord expired Screenshots / Backend Prereqs Update

[solderq35]

Issue and how to retrieve old Discord screenshots for reference:

• https://github.com/OSU-Sustainability-Office/osu-sustainability-office.github.io/issues/6

Use new preview deployment to help with testing: http://osu-so-wiki.s3-website-us-west-2.amazonaws.com/

There are some remaining screenshots on "backend pre-reqs" page that are expired, but I think that section should be revamped anyways (new instructions for iam user setup, no longer can get programmatic access key right away)

• https://github.com/OSU-Sustainability-Office/osu-sustainability-office.github.io/issues/5
• Fix in another future PR

[solderq35]

Finished updating expired screenshots, also revamped backend page for new IAM setup

http://localhost:3000/docs/backend_prereqs#aws

Also removed some unused boilerplate favicon files (leftover from the original project I based this wiki on)

[solderq35]

LGTM