Add highload NSM scenarios

[NikitaSkrynnik]

Description

Add highload NSM scenario with continuous NSC scaling. This scenario can be useful because it has revealed a lot of memory, interface and goroutine leaks. We also should collect pod's metrics and vpp interfaces after the test.

Scenario:

1. Make basic NSM setup
2. Deploy NSCs and NSEs, 0 replicas each
3. Scale NSCs and NSEs up to 30 pods
4. Wait for 1 minute
5. Check pings for all NSCs
6. Scale NSCs and NSEs down to 0 pods
7. Wait for 1 minute
8. Repeat steps 3-7 100 (maybe more?) times

Decomposition

• Write highload scenario in deployments-k8s - 3h
• Test the scenario locally - 3h
• Add collecting of metrics and vpp interfaces - 5h
• Test the scenario on CI - 7h