#48 Use traefik-public as public network and the project specific network only internally

Bump default version for Nginx to 1.21
Bump default version for Varnish to 6.0
Bump default version for Adminer to 4.6
Bump default version for phpMyAdmin to latest
Bump default version for WebGrind to 1
Add setting to turn on/off selenium service
Add service for elasticsearch

docker/l3d#55 Xdebug 3 comes with latest Wodby images

Set the value of $SSH_AUTH_SOCK instead of the env variable so that the containers can be started from within the dev container as well