Add Cache-Control header for assets served from the /public folder

[lalitpatel]

I noticed that we do not have a cache-control header set for our static images served from the /public folder. Setting a cache header would greatly reduce the number of request to the server for static assets and also speed up the page load for the end users.

My recommendation is to set cache for 100 days:

cache-control: public, max-age=8640000

Resources

• https://web.dev/http-cache/
• https://web.dev/codelab-http-cache/

[lalitpatel]

In production, we do not serve the static files via express, but directly via apache/nginx. This would therefore only affect development. I have however configured the header for those two paths in the deployments at aoe2cm.net (production) and cm.aoe2.se (staging) :+1:

Originally posted by @HSZemi in https://github.com/SiegeEngineers/aoe2cm2/pull/54#issuecomment-671906078