Added proper opcache configuration to improve performance

[oliverde8]

If we leave the default configuration opcache is not utilized at it's best.

Calling opcache_get_status(false); will return a cache_full. This means caches are invalidated quite often.

The issue comes from 2 points :

• Akeneo actually needs nearly 200mb of space. so the default 64 is not enough.
• There is around 15K php file in an Akeneo project so we need to increase the number of files as well to be on the safe side.

This has a non-negligible impact on performances on my dev machine, I go from ~600ms to ~500ms for loading a product page.

Let's note that if multiple php projects run on the same server these values need to take the sum of the needs of all projects.

This should also be changed in the docker files.