feat: add varnish WIP

[Chris53897]

This is just a proof of concept for varnish with APIP 2.6.
It is buggy. /docs need sometimes refreshed 4-6 times to work.
PWA, Vulcain, Mercure is not supported (or tested) at the moment.
I try to reuse varnish code from apip 2.5.

You may want to change these lines for your platform in /api/Dockerfile
#FROM varnish:${VARNISH_VERSION} AS api_platform_varnish

only temp for develop on Mac M1 - ARM64 not available for org. varnish

FROM beevelop/varnish AS api_platform_varnish

I am working on the deployment for kubernetes. Varnish is called but could not cache invalidation working.
Until this is fixed i am not gone push that.

[vincentchalamon]

Hi @Chris53897

Thanks for this proposal. If this POC is still in progress, have you considered Souin as a Caddy cache-handler instead of Varnish?

[Chris53897]

Hi @vincentchalamon
Unfortunately No. This PR/Topic priority has been lowered by company. And i changed company at the meantime.
Add the time of implementing i had a look at https://github.com/caddyserver/cache-handler But there was a lot of WIP and missing features. That was the reason i tried it with varnish.

[dunglas]

Closing in favor of #2383.