Services: Testing capabilites for bgp based exit tunnels.

[sargon]

In ffnord/ffnord-puppet-gateway#52 we get a new way to provide internet access to our infrastructure. So we should enable our service host in this experimental setup to also provide this service. Furthermore there is a second way to provide native IPv6 over ICVPN. Both ways have in common that they base on Route exchange via BGP, so this issue splits into following things to implement inside the services vm:

• GRE Tunnel
• ICVPN Integration
• Bird4/6 Route announcement

The Bird4/6 integration could be very simple, since we are in a test environment, this could also be a nice point to harden our export rules. So lets export fixed routes and import anything we get.