Update documentation for postings by ITDWeb and the content team

[dorothyyeager]

Summary

What we're after:
Now that we have new schedules, etc., it would be a good idea to make sure our "how to post a PDF" guidance is updated and in the shared drive.

Completion criteria

• Verify if existing documentation is updated and uploaded to shared drive.
• Archive the 18F version of the Content Guide
• Download current content guide so we have a copy and place in shared content folder.
• Bookmark both guides in the content channel.

[dorothyyeager]

Very easy to do when the guidance was in the content shared folder and in perfect shape! To help us remember the location of our materials, I've bookmarked the ITD posting guidance, the Content Guide and all the how to guides at the top of the content team Slack channel.