Added ability to output news/announcements on startup

[richbeales]

Background

Add the ability to read a file from the web (BULLETIN.md from our repo), and echo that to the user to keep them informed of community announcements, important news and new features, etc. Especially useful for those not on Discord.

Changes

Documentation

The file itself has information on how to suppress the output.

Test Plan

PR Quality Checklist

• My pull request is atomic and focuses on a single change.
• I have thoroughly tested my changes with multiple different prompts.
• I have considered potential risks and mitigations for my changes.
• I have documented my changes clearly and comprehensively.
• I have not snuck in any "extra" small tweaks changes

[p-i-]

This looks lovely.
I wonder if we should ONLY be displaying news if there is NEW news, i.e. writing the remote NEWS.md to a local _NEWS_REMOTE.md and on subsequent runs only displaying it if it's different.
Or showing it in green if it's new, and white if it's not.

If it displays each time, users will come to ignore it and won't notice when there's new news.
At the same time, it should display each run, as they'll forget what it said and not think to look for _NEWS_REMOTE.md

wotcha rkn?

[richbeales]

@p-i- done. It'll always show, but in a different colour if new.