enforce use of `assets` directory instead of `static`

[mattstratton]

This will take care of #14336

Now that we support the assets folder instead of static for images, we should update the code to ONLY use images in that folder and not use static.

Steps to accomplish this:

• Move all organizer/logo/speaker images for events that are NOT archived from static/events/xxxx to assets/events/xxx whatever (we need to leave the static directories for the archived events for Reasons) Move organizer, logo, and speaker images to the assets directory #14641
• update the code to only use the assets repo for organizer/speaker images enforce use of the assets directory for organizer/speaker images #14640
• update the code to only use the assets repo for logo shortcode
• update the code to only use the assets repo for front page logos adds enforcement of asset directory for square logos #14636
• fix all the images that are messed up/misidentified which will throw errors when we change the code :)