KVM: add configurable MAC/IP script hook for static ARP/NDP and routes

[wido]

Introduces a new agent.properties option vm.network.macip.script (absolute path, disabled by default) that BridgeVifDriver invokes on every NIC plug (VM start) and unplug (VM stop).

This is very useful in EVPN+VXLAN environments as it can reduce BUM traffic. By setting static ARP/NDP entries bridges can be configured using 'neigh_suppress on' as the ARP/NDP entries are already set statically by CloudStack.

[codecov]

Codecov Report

❌ Patch coverage is 27.27273% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 18.94%. Comparing base (82986f6) to head (53d11ed).

Files with missing lines	Patch %	Lines
...cloud/hypervisor/kvm/resource/BridgeVifDriver.java	23.80%	14 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #13495   +/-   ##
=========================================
  Coverage     18.94%   18.94%           
- Complexity    18363    18368    +5     
=========================================
  Files          6192     6192           
  Lines        556361   556383   +22     
  Branches      67908    67912    +4     
=========================================
+ Hits         105397   105408   +11     
- Misses       439393   439400    +7     
- Partials      11571    11575    +4     

Flag	Coverage Δ
uitests	3.51% <ø> (ø)
unittests	20.15% <27.27%> (+<0.01%)	⬆️

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[DaanHoogland]

clgtm, why not set your script as default value for the property @wido ? (if it is well tested and robust, that is)

[wido]

clgtm, why not set your script as default value for the property @wido ? (if it is well tested and robust, that is)

Thanks, the reason the script does not always execute is that it could break existing setups. Therefor it is not set by default.

[DaanHoogland]

clgtm, why not set your script as default value for the property @wido ? (if it is well tested and robust, that is)

Thanks, the reason the script does not always execute is that it could break existing setups. Therefor it is not set by default.

yeah, that is what I meant by robust ;) np, fine like this as well.