lp-gw - unified internet gateways

Additionally, various enhancements were made to lp-lxc and lp-smokeping in the process.

Differences over lp-fw / lp-isp combo

One role fits 'all' use cases / scenarios
Configuration has been greatly simplified
Performance improvements
- Overall streamlining of packet processing chain
- Throttle iptables -> conntrack lookups with (hash)limit
- Many logic blocks moved to separate chain with one entry condition
- Reduced amount of rules that are matched against every packet
- 'Minimal Mode' / ISP configuration only CTsaves outgoing packets
Per-interface feature toggles
Sane defaults introduced into role
TC script
- No longer run by LSB wrapper
- Gets one configuration and one instance per managed interface
LXC awareness for kernel parameters (still need solution for host params)
Lowered default CT timeouts for UDP to further reduce state inflation
Added 'validate' playbook for basic input validation
Introduced INT_NET IPset with containing internal networks
rt_tables entries are now intelligently created for each 'route' netif
Known Issues and Limitations
TC ruleset is still static, needs a proper python+pyroute2 implementation
As usual, documentation is incomplete
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