update the custom 404 page (new item URL & update the footer)

[christinklez]

Updates to the 404 page: https://github.com/ucldc/public_interface/blob/main/calisphere/templates/404.html

1: The "Toe stuck in a bowling ball" has a new item record URL:

• (older) broken item record URL: https://calisphere.org/item/8fb1debdaadcaa4ac974d9c420782669/
• current item record URL: https://calisphere.org/item/577c940ddc596a352f3516e408e1473e/
  • This current URL is on -stage: https://calisphere-stage.cdlib.org/item/577c940ddc596a352f3516e408e1473e/

2: The 404 page has a different footer happening. Option 1: Can we hook up the sitewide footer template instead? Option 2: Can we update the footer? Discussed on May 23 that a good practice for error pages is to make sure it does not rely on another source, as error pages indicate that something is wrong. We will update the 404 footer to match the sitewide template.

Here's the current footer: https://github.com/ucldc/public_interface/blob/main/calisphere/templates/calisphere/footer.html