rename topologies and add comment

topologies/1_1network_1host.yml → topologies/0-routers-1-network-1-host.yml

-name: 1-network-1-host
+# A simple topology with 1 debian 10 host in a network
+name: 0-routers-1-networks-1-hosts
 hosts:
   - name: debian10
     base_box: generic/debian10

topologies/2_1network_various_boxes.yml → topologies/0-routers-1-network-5-hosts.yml

+# A simple topology with various boxes in 1 network
 name: 1-network-various-boxes
 hosts:
   - name: debian10

topologies/3_1router_1host.yml → topologies/1-router-1-network-1-host.yml

+
+# 1 network with a host and a router
 name: 1-router-1-host
 hosts:
   - name: debian10

topologies/4_2networks.yml → topologies/1-router-2-networks-2-hosts.yml

+# Topology with one router connecting 2 separate networks, each with 1 host
 name: 2-networks
 hosts:
   - name: server