Community-Lab introduction

Modified script.txt from [adbf65b445] to [b369864a66].

    91     91     - Network and node managed by CN members.
    92     92     - Node admins must adhere to testbed terms and conditions.
    93     93     - This decouples testbed management from infrastructure ownership and mgmt.
    94     94   - Testbed management traffic uses a tinc mesh VPN:
    95     95     - Avoids problems with firewalls and private networks in nodes.
    96     96     - IPv6 is used to avoid address scarcity and incompatibility between CNs.
    97     97     - Link instability is tolerated by using short-lived mgmt connections.
    98         -- Gateways allow a testbed to span multiple CNs.
    99         -  - Connecting the mgmt net over external means (e.g. FEDERICA, the Internet).
   100         -  - Gateways can make the management network available to the Internet.
           98  +- Gateways are entry points to the mgmt network.
           99  +  - They can extend it over multiple CNs by external means (e.g. FEDERICA, the
          100  +    Internet).
          101  +  - They can also route the management network to the Internet.
   101    102   - A researcher runs the experiments of a slice in slivers each running in a
   102    103     different node.
   103    104   
   104    105   ** Slices, slivers and nodes
   105    106   # Diagram: Slices and slivers, two or three nodes with a few slivers on them,
   106    107   # each with a color identifying it with a slice.)
   107    108   - These concepts are inspired in PlanetLab.