Upgrade all services for Traefik v2 ; clean Compose files ; update doc

pica-openldap/docker-compose.yml

@@ -16,7 +16,7 @@ services:
     env_file:
       - ./secrets/pica-openldap.secrets
     labels:
-      traefik.frontend.rule: "Host:ldap.picasoft.net"
+      traefik.http.routers.ldap.rule: Host(`ldap.picasoft.net`)
       traefik.enable: true
       tls-certs-monitor.enable: true
       tls-certs-monitor.action: "restart"