customize nginx site for wayback deploy

[kmcelwee]

nginx configurations needed:

• [x] determine if we can use wayback in proxy mode within nginx
• [x] map 404 to archived 404 page in the archive crawl /404/
• [x] map 50* to archived 500 page in the archive crawl /_500/ (retain actual error code if possible)
• [x] disable iiif image urls
• ~proxy iiif images using generated map list~
  • ~update ansible passenger role to copy supporting files for use in nginx config~
• [x] use static version of sitemedia to override wayback content (for speed/efficiency)
  • [x] capture output from collectstatic in production and add to archive repo
• [x] local static copy of sitemaps so we can override/customize modification time/frequency
  • [x] #291
• [x] fix banner styles/overlap for image viewer so deep zoom button is clickable

[kmcelwee]

We're going to try addressing this with the nginx config after directly adding 404 and 500 to the seed list.

[rlskoeser]

• wayback should run on a separate port and be configured in a second nginx conf
  • need to figure out how to configure wayback not to prefix urls (proxy mode?)
• main nginx conf should use proxy_pass to wayback on 8080
• all customization (404s, static content, etc) should be in the outer nginx conf
• use a maintenance location for 404/500; see https://dev.to/shano/easy-maintenance-mode-with-nginx-2c6g and https://github.com/pulibrary/princeton_ansible/blob/main/roles/nginxplus/files/conf/http/templates/staging-maintenance.conf

revise ansible playbook to run passenger role twice to generate & enable the two configs