Create a new guide to set up virtual routers.

[Metallion]

Problem

The current installation guide sets up OpenVNet for two interfaces in a single virtual network. This is great as a first introduction to OpenVNet but doesn't show off what it can do yet. We need to add many new guides to complement it.

Solution

For starters let's add a guide that takes the same LXC based environment from the installation guide and sets up a two virtual networks with a router between them.

Currently the installation guide environment looks like this.

https://www.dropbox.com/s/dezarv561fg7sdj/vnet_minimum.png

That means the installation guide's virtual network looks like this.

      +------------------+         +-------------------+               
      |                  |         |                   |               
      |   Interface 1    |         |   Interface 2     |               
      |   10.100.0.10    |         |   10.100.0.10     |               
      |                  |         |                   |               
      +--------+---------+         +--------+----------+               
               |                            |                          
               |                            |                          
               |                            |                          
               |                            |                          
               |                            |             10.100.0.0/24
               |                            |                          
 --------------+----------------------------+------------------------

The router guide should create the following virtual network instead.

          +----------------+                      +----------------+       
          |                |                      |                |       
          |   Interface 1  |                      |   Interface 2  |       
          |   192.168.0.10 |                      |   172.16.0.10  |       
          |                |                      |                |       
          +-------+--------+                      +-----+----------+       
                  |                                     |                  
                  |                                     |                  
                  |                                     |                  
                  |                                     |                  
192.168.0.0/24    |                                     |     172.16.0.0/24
                  |                                     |                  
     +------------+--------+----+      +------+---------+----------+       
                           |                  |                            
                           |                  |                            
                           |                  |                            
             +-------------+-----+     +------+-----------+                
             |                   |     |                  |                
             |   Simulated       |     |   Simulated      |                
             |   interface       |     |   interface      |                
             |   192.168.0.1     |     |   172.16.0.1     |                
             |                   |     |                  |                
             +-------------------+-----+------------------+                
             |                                            |                
             |                                            |                
             |                                            |                
             |        OpenVNet simulated router           |                
             |                                            |                
             |                                            |                
             |                                            |                
             +--------------------------------------------+                

[Metallion]

You can reference the router related integration tests to see how exactly routers are created in OpenVNet.

Keep in mind this yet unmerged change to the intergration test that states router network services are no longer needed. Removing those services from the code will be dealt with in another issue.