app: add vpn tunneling benchmark with simulated network with different bandwidth/latency

[pymq]

Results:

+-----------------------------+---------+-----------------+-------------------+-------------+-------------+
|          SCENARIO           | LATENCY | BANDWIDTH LIMIT | ACTUAL THROUGHPUT | UTILIZATION | PACKET LOSS |
+-----------------------------+---------+-----------------+-------------------+-------------+-------------+
| Fiber_300Mbps_1ms           | 1ms     | 300 Mbps        | 227.02 Mbps       | 75.67 %     | 98.04 %     |
| LongDistFiber_300Mbps_200ms | 200ms   | 300 Mbps        | 30.82 Mbps        | 10.27 %     | 99.78 %     |
| Cable_10Mbps_1ms            | 1ms     | 10 Mbps         | 9.72 Mbps         | 97.22 %     | 99.93 %     |
| Cable_10Mbps_10ms           | 10ms    | 10 Mbps         | 9.74 Mbps         | 97.38 %     | 99.94 %     |
| Cable_10Mbps_100ms          | 100ms   | 10 Mbps         | 7.97 Mbps         | 79.66 %     | 99.95 %     |
| Cable_10Mbps_200ms          | 200ms   | 10 Mbps         | 6.95 Mbps         | 69.52 %     | 99.96 %     |
| LongDistCable_10Mbps_300ms  | 300ms   | 10 Mbps         | 6.38 Mbps         | 63.76 %     | 99.96 %     |
| Cable_50Mbps_1ms            | 1ms     | 50 Mbps         | 48.56 Mbps        | 97.12 %     | 99.68 %     |
| Cable_50Mbps_10ms           | 10ms    | 50 Mbps         | 48.05 Mbps        | 96.10 %     | 99.71 %     |
| Cable_50Mbps_100ms          | 100ms   | 50 Mbps         | 34.14 Mbps        | 68.28 %     | 99.75 %     |
| Cable_50Mbps_200ms          | 200ms   | 50 Mbps         | 19.95 Mbps        | 39.91 %     | 99.86 %     |
| LongDistCable_50Mbps_300ms  | 300ms   | 50 Mbps         | 14.23 Mbps        | 28.45 %     | 99.90 %     |
| DSL_20Mbps_25ms             | 25ms    | 20 Mbps         | 18.12 Mbps        | 90.61 %     | 99.88 %     |
| LTE_30Mbps_40ms             | 40ms    | 30 Mbps         | 26.77 Mbps        | 89.23 %     | 99.82 %     |
+-----------------------------+---------+-----------------+-------------------+-------------+-------------+

As observed in real testing, throughput degrades significantly with high latency. Fixes will be coming in future PRs.