Get rid of Apache web server in favor of nginx

[Hixon10]

Hello,

Current implementation uses wordpress:latest docker image, which uses Apache web server internally. So, we have the following request flow:

user browser -> nginx -> apache -> php -> wordpress 

it would be nice to get rid of Apache web server. Probably, we may reuse nginx, which we have because of nginx-proxy-companion. In that case we will have the following flow:

user browser -> nginx -> php fpm -> wordpress

This change reduces needed computational resources.