Use underlay prefix and two harcoded bytes for traffic isolation

[guvenc]

Do not isolate only the ip in ipv6 encapsulated packets but also the specific subnet used by dpservice on a given node.

[byteocean]

The changes passed the benchmark tests on our lab machines, both the offloading and non-offloading mode.

[PlagueCZ]

Small details found.

Also I would like to discuss the prefix idea

[PlagueCZ]

I finished the needed changes, moved to range d000..dfff, ported changes to async flow rules and then removed all rules for virtual services as they are no longer necessary.

Code is much simpler everywhere now.

I documented my prefix schema in docs/deployment/ and added support for vnf_type to be encoded in the address (optional in meson). I reordered vnf_type because I implemented this change in metalnet already and ordered it to be easily remembered, only later finding that the same enum already exists in dpservice. This is also why the one test needed to change (wcmp hash changed).

I tested on pytest with HW (mellanox) tests, and also deployed in OSC, both normal and multiport setup, i.e. both sync and async rules are fully tested and working fine. I believe Florin will be testing the running of a separate IPIP tunnel in parallel to dpservice on Monday.

I also moved dp_rte_flow_init module to dp_rte_flow_isolation to be consistent with the async version.

[PlagueCZ]

Florin confirmed that independent IPIP traffic is now able to work alongside dpservice. This is on async multiport eswitch setup.

[guvenc]

LGTM